diff --git a/packages/xrpl/test/client/autofill.test.ts b/packages/xrpl/test/client/autofill.test.ts
index cfb93f2c..5fed3c94 100644
--- a/packages/xrpl/test/client/autofill.test.ts
+++ b/packages/xrpl/test/client/autofill.test.ts
@@ -18,6 +18,7 @@ import { assertRejects } from '../testUtils'
 const Fee = '10'
 const Sequence = 1432
 const LastLedgerSequence = 2908734
+const NetworkID = 21338
 
 describe('client.autofill', function () {
   let testContext: XrplTestContext
@@ -35,12 +36,14 @@ describe('client.autofill', function () {
       Fee,
       Sequence,
       LastLedgerSequence,
+      NetworkID,
     }
     const txResult = await testContext.client.autofill(tx)
 
     assert.strictEqual(txResult.Fee, Fee)
     assert.strictEqual(txResult.Sequence, Sequence)
     assert.strictEqual(txResult.LastLedgerSequence, LastLedgerSequence)
+    assert.strictEqual(txResult.NetworkID, NetworkID)
   })
 
   it('converts Account & Destination X-address to their classic address', async function () {
@@ -58,6 +61,10 @@ describe('client.autofill', function () {
       'server_info',
       rippled.server_info.normal,
     )
+    testContext.mockRippled!.addResponse(
+      'server_info',
+      rippled.server_info.normal,
+    )
     testContext.mockRippled!.addResponse('ledger', rippled.ledger.normal)
 
     const txResult = await testContext.client.autofill(tx)
@@ -76,6 +83,7 @@ describe('client.autofill', function () {
       Authorize: 'rpZc4mVfWUif9CRoHRKKcmhu1nx2xktxBo',
       Fee,
       LastLedgerSequence,
+      NetworkID,
     }
     testContext.mockRippled!.addResponse('account_info', {
       status: 'success',
@@ -101,6 +109,10 @@ describe('client.autofill', function () {
       'server_info',
       rippled.server_info.normal,
     )
+    testContext.mockRippled!.addResponse(
+      'server_info',
+      rippled.server_info.normal,
+    )
     testContext.mockRippled!.addResponse(
       'account_objects',
       rippled.account_objects.normal,
@@ -113,6 +125,7 @@ describe('client.autofill', function () {
       Fee,
       Sequence,
       LastLedgerSequence,
+      NetworkID,
     }
 
     await assertRejects(testContext.client.autofill(tx), XrplError)
@@ -126,6 +139,7 @@ describe('client.autofill', function () {
         Authorize: 'rpZc4mVfWUif9CRoHRKKcmhu1nx2xktxBo',
         Sequence,
         LastLedgerSequence,
+        NetworkID,
       }
       testContext.mockRippled!.addResponse(
         'server_info',
@@ -155,6 +169,10 @@ describe('client.autofill', function () {
         'server_info',
         rippled.server_info.normal,
       )
+      testContext.mockRippled!.addResponse(
+        'server_info',
+        rippled.server_info.normal,
+      )
 
       const txResult = await testContext.client.autofill(tx)
       assert.strictEqual(txResult.Fee, '399')
@@ -171,6 +189,10 @@ describe('client.autofill', function () {
         rippled.account_info.normal,
       )
       testContext.mockRippled!.addResponse('ledger', rippled.ledger.normal)
+      testContext.mockRippled!.addResponse(
+        'server_info',
+        rippled.server_info.normal,
+      )
       testContext.mockRippled!.addResponse('server_state', {
         status: 'success',
         type: 'response',
@@ -214,6 +236,10 @@ describe('client.autofill', function () {
         'server_info',
         rippled.server_info.normal,
       )
+      testContext.mockRippled!.addResponse(
+        'server_info',
+        rippled.server_info.normal,
+      )
       const txResult = await testContext.client.autofill(tx, 4)
 
       assert.strictEqual(txResult.Fee, '459')
@@ -227,6 +253,7 @@ describe('client.autofill', function () {
       Authorize: 'rpZc4mVfWUif9CRoHRKKcmhu1nx2xktxBo',
       Fee,
       Sequence,
+      NetworkID,
     }
     testContext.mockRippled!.addResponse('ledger', {
       status: 'success',
@@ -272,9 +299,37 @@ describe('client.autofill', function () {
         },
       },
     })
+    testContext.mockRippled!.addResponse(
+      'server_info',
+      rippled.server_info.normal,
+    )
     const txResult = await testContext.client.autofill(tx)
     assert.strictEqual(txResult.Fee, '12')
     assert.strictEqual(txResult.Sequence, 23)
     assert.strictEqual(txResult.LastLedgerSequence, 9038234)
+    assert.strictEqual(txResult.NetworkID, 21338)
+  })
+
+  it("should autofill NetworkID when it's missing", async function () {
+    const tx: Transaction = {
+      TransactionType: 'DepositPreauth',
+      Account: 'rGWrZyQqhTp9Xu7G5Pkayo7bXjH4k4QYpf',
+      Authorize: 'rpZc4mVfWUif9CRoHRKKcmhu1nx2xktxBo',
+      Fee,
+      LastLedgerSequence,
+      Sequence,
+    }
+    testContext.mockRippled!.addResponse('server_info', {
+      status: 'success',
+      type: 'response',
+      result: {
+        info: {
+          network_id: 21338,
+        },
+      },
+    })
+    const txResult = await testContext.client.autofill(tx)
+
+    assert.strictEqual(txResult.NetworkID, 21338)
   })
 })
diff --git a/packages/xrpl/test/client/submit.test.ts b/packages/xrpl/test/client/submit.test.ts
index c2c57890..64182f4c 100644
--- a/packages/xrpl/test/client/submit.test.ts
+++ b/packages/xrpl/test/client/submit.test.ts
@@ -34,6 +34,7 @@ describe('client.submit', function () {
       Sequence: 1,
       Fee: '12',
       LastLedgerSequence: 12312,
+      NetworkID: 21338,
     }
 
     it('should submit an unsigned transaction', async function () {
@@ -83,6 +84,7 @@ describe('client.submit', function () {
       LastLedgerSequence: 12312,
       Amount: '20000000',
       Fee: '12',
+      NetworkID: 21338,
       SigningPubKey:
         '030E58CDD076E798C84755590AAF6237CA8FAE821070A59F648B517A30DC6F589D',
       TxnSignature:
diff --git a/packages/xrpl/test/fixtures/rippled/serverInfo.json b/packages/xrpl/test/fixtures/rippled/serverInfo.json
index 55ce67d0..c0bf1147 100644
--- a/packages/xrpl/test/fixtures/rippled/serverInfo.json
+++ b/packages/xrpl/test/fixtures/rippled/serverInfo.json
@@ -12,6 +12,7 @@
         "converge_time_s": 2.007,
         "proposers": 4
       },
+      "network_id": 21338,
       "load_factor": 1,
       "peers": 53,
       "pubkey_node": "n94wWvFUmaKGYrKUGgpv1DyYgDeXRGdACkNQaSe7zJiy5Znio7UC",
diff --git a/packages/xrpl/test/models/NFTokenAcceptOffer.test.ts b/packages/xrpl/test/models/NFTokenAcceptOffer.test.ts
index f53b14c3..bbc2c87e 100644
--- a/packages/xrpl/test/models/NFTokenAcceptOffer.test.ts
+++ b/packages/xrpl/test/models/NFTokenAcceptOffer.test.ts
@@ -19,6 +19,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenBuyOffer: NFTOKEN_BUY_OFFER,
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -32,6 +33,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenSellOffer: NFTOKEN_SELL_OFFER,
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -44,6 +46,7 @@ describe('NFTokenAcceptOffer', function () {
       TransactionType: 'NFTokenAcceptOffer',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -62,6 +65,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenBuyOffer: NFTOKEN_BUY_OFFER,
       NFTokenBrokerFee: '1',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -80,6 +84,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenSellOffer: NFTOKEN_SELL_OFFER,
       NFTokenBrokerFee: '1',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -98,6 +103,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenBuyOffer: NFTOKEN_BUY_OFFER,
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -113,6 +119,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenBrokerFee: '1',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -128,6 +135,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenBuyOffer: NFTOKEN_BUY_OFFER,
       NFTokenBrokerFee: '0',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -147,6 +155,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenBuyOffer: NFTOKEN_BUY_OFFER,
       NFTokenBrokerFee: '-1',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -166,6 +175,7 @@ describe('NFTokenAcceptOffer', function () {
       NFTokenBuyOffer: NFTOKEN_BUY_OFFER,
       NFTokenBrokerFee: 1,
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
diff --git a/packages/xrpl/test/models/NFTokenBurn.test.ts b/packages/xrpl/test/models/NFTokenBurn.test.ts
index 9d799a32..3bd1dbe2 100644
--- a/packages/xrpl/test/models/NFTokenBurn.test.ts
+++ b/packages/xrpl/test/models/NFTokenBurn.test.ts
@@ -17,6 +17,7 @@ describe('NFTokenBurn', function () {
       NFTokenID: TOKEN_ID,
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
@@ -29,6 +30,7 @@ describe('NFTokenBurn', function () {
       TransactionType: 'NFTokenBurn',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: 2147483648,
     } as any
diff --git a/packages/xrpl/test/models/NFTokenCancelOffer.test.ts b/packages/xrpl/test/models/NFTokenCancelOffer.test.ts
index d0202995..b19129c6 100644
--- a/packages/xrpl/test/models/NFTokenCancelOffer.test.ts
+++ b/packages/xrpl/test/models/NFTokenCancelOffer.test.ts
@@ -14,6 +14,7 @@ describe('NFTokenCancelOffer', function () {
   it(`verifies valid NFTokenCancelOffer`, function () {
     const validNFTokenCancelOffer = {
       TransactionType: 'NFTokenCancelOffer',
+      NetworkID: 21338,
       NFTokenOffers: [BUY_OFFER],
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
@@ -28,6 +29,7 @@ describe('NFTokenCancelOffer', function () {
     const invalid = {
       TransactionType: 'NFTokenCancelOffer',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
+      NetworkID: 21338,
       Fee: '5000000',
       Sequence: 2470665,
       Flags: 2147483648,
@@ -44,6 +46,7 @@ describe('NFTokenCancelOffer', function () {
     const invalid = {
       TransactionType: 'NFTokenCancelOffer',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
+      NetworkID: 21338,
       NFTokenOffers: [],
       Fee: '5000000',
       Sequence: 2470665,
diff --git a/packages/xrpl/test/models/NFTokenCreateOffer.test.ts b/packages/xrpl/test/models/NFTokenCreateOffer.test.ts
index b874f2b1..bcfd6239 100644
--- a/packages/xrpl/test/models/NFTokenCreateOffer.test.ts
+++ b/packages/xrpl/test/models/NFTokenCreateOffer.test.ts
@@ -14,6 +14,7 @@ describe('NFTokenCreateOffer', function () {
   it(`verifies valid NFTokenCreateOffer buyside`, function () {
     const validNFTokenCreateOffer = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       NFTokenID: NFTOKEN_ID,
       Amount: '1',
       Owner: 'r9LqNeG6qHxjeUocjvVki2XR35weJ9mZgQ',
@@ -30,6 +31,7 @@ describe('NFTokenCreateOffer', function () {
   it(`verifies valid NFTokenCreateOffer sellside`, function () {
     const validNFTokenCreateOffer = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       NFTokenID: NFTOKEN_ID,
       Amount: '1',
       Flags: NFTokenCreateOfferFlags.tfSellNFToken,
@@ -46,6 +48,7 @@ describe('NFTokenCreateOffer', function () {
   it(`verifies w/ 0 Amount NFTokenCreateOffer sellside`, function () {
     const validNFTokenCreateOffer = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       NFTokenID: NFTOKEN_ID,
       Amount: '0',
       Flags: NFTokenCreateOfferFlags.tfSellNFToken,
@@ -62,6 +65,7 @@ describe('NFTokenCreateOffer', function () {
   it(`throws w/ Account === Owner`, function () {
     const invalid = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       NFTokenID: NFTOKEN_ID,
       Amount: '1',
       Expiration: 1000,
@@ -81,6 +85,7 @@ describe('NFTokenCreateOffer', function () {
   it(`throws w/ Account === Destination`, function () {
     const invalid = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       NFTokenID: NFTOKEN_ID,
       Amount: '1',
       Flags: NFTokenCreateOfferFlags.tfSellNFToken,
@@ -101,6 +106,7 @@ describe('NFTokenCreateOffer', function () {
   it(`throws w/out NFTokenID`, function () {
     const invalid = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       Amount: '1',
       Owner: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXe',
       Expiration: 1000,
@@ -120,6 +126,7 @@ describe('NFTokenCreateOffer', function () {
   it(`throws w/ invalid Amount`, function () {
     const invalid = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       NFTokenID: NFTOKEN_ID,
       Amount: 1,
       Owner: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXe',
@@ -140,6 +147,7 @@ describe('NFTokenCreateOffer', function () {
   it(`throws w/ missing Amount`, function () {
     const invalid = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       Owner: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXe',
       Expiration: 1000,
       NFTokenID: NFTOKEN_ID,
@@ -159,6 +167,7 @@ describe('NFTokenCreateOffer', function () {
   it(`throws w/ Owner for sell offer`, function () {
     const invalid = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       Expiration: 1000,
       Owner: 'r9LqNeG6qHxjeUocjvVki2XR35weJ9mZgQ',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
@@ -179,6 +188,7 @@ describe('NFTokenCreateOffer', function () {
   it(`throws w/out Owner for buy offer`, function () {
     const invalid = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       Expiration: 1000,
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Amount: '1',
@@ -197,6 +207,7 @@ describe('NFTokenCreateOffer', function () {
   it(`throws w/ 0 Amount for buy offer`, function () {
     const invalid = {
       TransactionType: 'NFTokenCreateOffer',
+      NetworkID: 21338,
       Expiration: 1000,
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Owner: 'r9LqNeG6qHxjeUocjvVki2XR35weJ9mZgQ',
diff --git a/packages/xrpl/test/models/NFTokenMint.test.ts b/packages/xrpl/test/models/NFTokenMint.test.ts
index 89ad7175..91042105 100644
--- a/packages/xrpl/test/models/NFTokenMint.test.ts
+++ b/packages/xrpl/test/models/NFTokenMint.test.ts
@@ -18,6 +18,7 @@ describe('NFTokenMint', function () {
       TransactionType: 'NFTokenMint',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: NFTokenMintFlags.tfTransferable,
       NFTokenTaxon: 0,
@@ -34,6 +35,7 @@ describe('NFTokenMint', function () {
       TransactionType: 'NFTokenMint',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: NFTokenMintFlags.tfTransferable,
       Issuer: 'r9LqNeG6qHxjeUocjvVki2XR35weJ9mZgQ',
@@ -53,6 +55,7 @@ describe('NFTokenMint', function () {
       TransactionType: 'NFTokenMint',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: NFTokenMintFlags.tfTransferable,
       Issuer: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
@@ -73,6 +76,7 @@ describe('NFTokenMint', function () {
       TransactionType: 'NFTokenMint',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
       Fee: '5000000',
+      NetworkID: 21338,
       Sequence: 2470665,
       Flags: NFTokenMintFlags.tfTransferable,
       NFTokenTaxon: 0,
diff --git a/packages/xrpl/test/models/accountDelete.test.ts b/packages/xrpl/test/models/accountDelete.test.ts
index e742f3ca..3dc89251 100644
--- a/packages/xrpl/test/models/accountDelete.test.ts
+++ b/packages/xrpl/test/models/accountDelete.test.ts
@@ -13,6 +13,7 @@ describe('AccountDelete', function () {
     const validAccountDelete = {
       TransactionType: 'AccountDelete',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
+      NetworkID: 21338,
       Destination: 'rPT1Sjq2YGrBMTttX4GZHjKu9dyfzbpAYe',
       DestinationTag: 13,
       Fee: '5000000',
@@ -27,6 +28,7 @@ describe('AccountDelete', function () {
     const invalidDestination = {
       TransactionType: 'AccountDelete',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
+      NetworkID: 21338,
       Fee: '5000000',
       Sequence: 2470665,
       Flags: 2147483648,
@@ -49,6 +51,7 @@ describe('AccountDelete', function () {
     const invalidDestination = {
       TransactionType: 'AccountDelete',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
+      NetworkID: 21338,
       Destination: 65478965,
       Fee: '5000000',
       Sequence: 2470665,
@@ -71,6 +74,7 @@ describe('AccountDelete', function () {
     const invalidDestinationTag = {
       TransactionType: 'AccountDelete',
       Account: 'rWYkbWkCeg8dP6rXALnjgZSjjLyih5NXm',
+      NetworkID: 21338,
       Destination: 'rPT1Sjq2YGrBMTttX4GZHjKu9dyfzbpAYe',
       DestinationTag: 'gvftyujnbv',
       Fee: '5000000',
diff --git a/packages/xrpl/test/models/accountSet.test.ts b/packages/xrpl/test/models/accountSet.test.ts
index 3d9ba484..b32d4ad6 100644
--- a/packages/xrpl/test/models/accountSet.test.ts
+++ b/packages/xrpl/test/models/accountSet.test.ts
@@ -15,6 +15,7 @@ describe('AccountSet', function () {
     account = {
       TransactionType: 'AccountSet',
       Account: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
+      NetworkID: 21338,
       Fee: '12',
       Sequence: 5,
       Domain: '6578616D706C652E636F6D',
diff --git a/packages/xrpl/test/models/baseTransaction.test.ts b/packages/xrpl/test/models/baseTransaction.test.ts
index c21a387d..c68aca56 100644
--- a/packages/xrpl/test/models/baseTransaction.test.ts
+++ b/packages/xrpl/test/models/baseTransaction.test.ts
@@ -13,6 +13,7 @@ describe('BaseTransaction', function () {
     const txJson = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       Fee: '12',
       Sequence: 100,
       AccountTxnID: 'DEADBEEF',
@@ -63,6 +64,7 @@ describe('BaseTransaction', function () {
     const txJson = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
     }
 
     assert.doesNotThrow(() => validateBaseTransaction(txJson))
@@ -72,6 +74,7 @@ describe('BaseTransaction', function () {
     const invalidFee = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       Fee: 1000,
     } as any
 
@@ -86,6 +89,7 @@ describe('BaseTransaction', function () {
     const invalidSeq = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       Sequence: '145',
     } as any
 
@@ -100,6 +104,7 @@ describe('BaseTransaction', function () {
     const invalidID = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       AccountTxnID: ['WRONG'],
     } as any
 
@@ -114,6 +119,7 @@ describe('BaseTransaction', function () {
     const invalidLastLedgerSequence = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       LastLedgerSequence: '1000',
     } as any
 
@@ -128,6 +134,7 @@ describe('BaseTransaction', function () {
     const invalidSourceTag = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       SourceTag: ['ARRAY'],
     } as any
 
@@ -142,6 +149,7 @@ describe('BaseTransaction', function () {
     const invalidSigningPubKey = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       SigningPubKey: 1000,
     } as any
 
@@ -156,6 +164,7 @@ describe('BaseTransaction', function () {
     const invalidTicketSequence = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       TicketSequence: '1000',
     } as any
 
@@ -170,6 +179,7 @@ describe('BaseTransaction', function () {
     const invalidTxnSignature = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       TxnSignature: 1000,
     } as any
 
@@ -180,10 +190,25 @@ describe('BaseTransaction', function () {
     )
   })
 
+  it(`Handles invalid NetworkID`, function () {
+    const invalidTxnSignature = {
+      Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
+      TransactionType: 'Payment',
+      NetworkID: '21338',
+    } as any
+
+    assert.throws(
+      () => validateBaseTransaction(invalidTxnSignature),
+      ValidationError,
+      'BaseTransaction: invalid NetworkID',
+    )
+  })
+
   it(`Handles invalid Signers`, function () {
     const invalidSigners = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       Signers: [],
     } as any
 
@@ -196,6 +221,7 @@ describe('BaseTransaction', function () {
     const invalidSigners2 = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       Signers: [
         {
           Signer: {
@@ -216,6 +242,7 @@ describe('BaseTransaction', function () {
     const invalidMemo = {
       Account: 'r97KeayHuEsDwyU1yPBVtMLLoQr79QcRFe',
       TransactionType: 'Payment',
+      NetworkID: 21338,
       Memos: [
         {
           Memo: {
diff --git a/packages/xrpl/test/models/checkCancel.test.ts b/packages/xrpl/test/models/checkCancel.test.ts
index 1cf87834..5452876f 100644
--- a/packages/xrpl/test/models/checkCancel.test.ts
+++ b/packages/xrpl/test/models/checkCancel.test.ts
@@ -13,6 +13,7 @@ describe('CheckCancel', function () {
     const validCheckCancel = {
       Account: 'rUn84CUYbNjRoTQ6mSW7BVJPSVJNLb1QLo',
       TransactionType: 'CheckCancel',
+      NetworkID: 21338,
       CheckID:
         '49647F0D748DC3FE26BDACBC57F251AADEFFF391403EC9BF87C97F67E9977FB0',
     } as any
diff --git a/packages/xrpl/test/models/checkCash.test.ts b/packages/xrpl/test/models/checkCash.test.ts
index 918bdeb3..4cb8f255 100644
--- a/packages/xrpl/test/models/checkCash.test.ts
+++ b/packages/xrpl/test/models/checkCash.test.ts
@@ -13,6 +13,7 @@ describe('CheckCash', function () {
     const validCheckCash = {
       Account: 'rfkE1aSy9G8Upk4JssnwBxhEv5p4mn2KTy',
       TransactionType: 'CheckCash',
+      NetworkID: 21338,
       Amount: '100000000',
       CheckID:
         '838766BA2B995C00744175F69A1B11E32C3DBC40E64801A4056FCBD657F57334',
@@ -27,6 +28,7 @@ describe('CheckCash', function () {
     const invalidCheckID = {
       Account: 'rfkE1aSy9G8Upk4JssnwBxhEv5p4mn2KTy',
       TransactionType: 'CheckCash',
+      NetworkID: 21338,
       Amount: '100000000',
       CheckID: 83876645678567890,
     } as any
@@ -47,6 +49,7 @@ describe('CheckCash', function () {
     const invalidAmount = {
       Account: 'rfkE1aSy9G8Upk4JssnwBxhEv5p4mn2KTy',
       TransactionType: 'CheckCash',
+      NetworkID: 21338,
       Amount: 100000000,
       CheckID:
         '838766BA2B995C00744175F69A1B11E32C3DBC40E64801A4056FCBD657F57334',
@@ -68,6 +71,7 @@ describe('CheckCash', function () {
     const invalidDeliverMin = {
       Account: 'rfkE1aSy9G8Upk4JssnwBxhEv5p4mn2KTy',
       TransactionType: 'CheckCash',
+      NetworkID: 21338,
       Amount: '100000000',
       DeliverMin: 852156963,
       CheckID:
@@ -90,6 +94,7 @@ describe('CheckCash', function () {
     const invalidDeliverMin = {
       Account: 'rfkE1aSy9G8Upk4JssnwBxhEv5p4mn2KTy',
       TransactionType: 'CheckCash',
+      NetworkID: 21338,
       DeliverMin: 852156963,
       CheckID:
         '838766BA2B995C00744175F69A1B11E32C3DBC40E64801A4056FCBD657F57334',
diff --git a/packages/xrpl/test/models/checkCreate.test.ts b/packages/xrpl/test/models/checkCreate.test.ts
index e1985614..ced30f1b 100644
--- a/packages/xrpl/test/models/checkCreate.test.ts
+++ b/packages/xrpl/test/models/checkCreate.test.ts
@@ -20,6 +20,7 @@ describe('CheckCreate', function () {
         '6F1DFD1D0FE8A32E40E1F2C05CF1C15545BAB56B617F9C6C2D63A6B704BEF59B',
       DestinationTag: 1,
       Fee: '12',
+      NetworkID: 21338,
     } as any
 
     assert.doesNotThrow(() => validateCheckCreate(validCheck))
@@ -37,6 +38,7 @@ describe('CheckCreate', function () {
         '6F1DFD1D0FE8A32E40E1F2C05CF1C15545BAB56B617F9C6C2D63A6B704BEF59B',
       DestinationTag: 1,
       Fee: '12',
+      NetworkID: 21338,
     } as any
 
     assert.throws(
@@ -62,6 +64,7 @@ describe('CheckCreate', function () {
         '6F1DFD1D0FE8A32E40E1F2C05CF1C15545BAB56B617F9C6C2D63A6B704BEF59B',
       DestinationTag: 1,
       Fee: '12',
+      NetworkID: 21338,
     } as any
 
     assert.throws(
@@ -80,6 +83,7 @@ describe('CheckCreate', function () {
     const invalidDestinationTag = {
       TransactionType: 'CheckCreate',
       Account: 'rUn84CUYbNjRoTQ6mSW7BVJPSVJNLb1QLo',
+      NetworkID: 21338,
       Destination: 'rfkE1aSy9G8Upk4JssnwBxhEv5p4mn2KTy',
       SendMax: '100000000',
       Expiration: 570113521,
@@ -112,6 +116,7 @@ describe('CheckCreate', function () {
         '6F1DFD1D0FE8A32E40E1F2C05CF1C15545BAB56B617F9C6C2D63A6B704BEF59B',
       DestinationTag: 1,
       Fee: '12',
+      NetworkID: 21338,
     } as any
 
     assert.throws(
@@ -136,6 +141,7 @@ describe('CheckCreate', function () {
       InvoiceID: 789656963258531,
       DestinationTag: 1,
       Fee: '12',
+      NetworkID: 21338,
     } as any
 
     assert.throws(
diff --git a/packages/xrpl/test/models/depositPreauth.test.ts b/packages/xrpl/test/models/depositPreauth.test.ts
index 11e33057..a70238eb 100644
--- a/packages/xrpl/test/models/depositPreauth.test.ts
+++ b/packages/xrpl/test/models/depositPreauth.test.ts
@@ -15,6 +15,7 @@ describe('DepositPreauth', function () {
     depositPreauth = {
       TransactionType: 'DepositPreauth',
       Account: 'rUn84CUYbNjRoTQ6mSW7BVJPSVJNLb1QLo',
+      NetworkID: 21338,
     } as any
   })
 
diff --git a/packages/xrpl/test/models/escrowCancel.test.ts b/packages/xrpl/test/models/escrowCancel.test.ts
index c4650a92..1d4408d9 100644
--- a/packages/xrpl/test/models/escrowCancel.test.ts
+++ b/packages/xrpl/test/models/escrowCancel.test.ts
@@ -17,6 +17,7 @@ describe('EscrowCancel', function () {
       Account: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       Owner: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       OfferSequence: 7,
+      NetworkID: 21338,
     }
   })
 
diff --git a/packages/xrpl/test/models/escrowCreate.test.ts b/packages/xrpl/test/models/escrowCreate.test.ts
index 20ccf40f..56bcc294 100644
--- a/packages/xrpl/test/models/escrowCreate.test.ts
+++ b/packages/xrpl/test/models/escrowCreate.test.ts
@@ -15,6 +15,7 @@ describe('EscrowCreate', function () {
     escrow = {
       Account: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       TransactionType: 'EscrowCreate',
+      NetworkID: 21338,
       Amount: '10000',
       Destination: 'rsA2LpzuawewSBQXkiju3YQTMzW13pAAdW',
       CancelAfter: 533257958,
diff --git a/packages/xrpl/test/models/escrowFinish.test.ts b/packages/xrpl/test/models/escrowFinish.test.ts
index 4caf04a7..05c8b00f 100644
--- a/packages/xrpl/test/models/escrowFinish.test.ts
+++ b/packages/xrpl/test/models/escrowFinish.test.ts
@@ -15,6 +15,7 @@ describe('EscrowFinish', function () {
     escrow = {
       Account: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       TransactionType: 'EscrowFinish',
+      NetworkID: 21338,
       Owner: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       OfferSequence: 7,
       Condition:
diff --git a/packages/xrpl/test/models/offerCancel.test.ts b/packages/xrpl/test/models/offerCancel.test.ts
index 2aea40c3..cae9f88a 100644
--- a/packages/xrpl/test/models/offerCancel.test.ts
+++ b/packages/xrpl/test/models/offerCancel.test.ts
@@ -15,6 +15,7 @@ describe('OfferCancel', function () {
     offer = {
       Account: 'rnKiczmiQkZFiDES8THYyLA2pQohC5C6EF',
       Fee: '10',
+      NetworkID: 21338,
       LastLedgerSequence: 65477334,
       OfferSequence: 60797528,
       Sequence: 60797535,
diff --git a/packages/xrpl/test/models/offerCreate.test.ts b/packages/xrpl/test/models/offerCreate.test.ts
index d3fa1c9d..ae2b0cd1 100644
--- a/packages/xrpl/test/models/offerCreate.test.ts
+++ b/packages/xrpl/test/models/offerCreate.test.ts
@@ -13,6 +13,7 @@ describe('OfferCreate', function () {
     const offer = {
       Account: 'r3rhWeE31Jt5sWmi4QiGLMZnY3ENgqw96W',
       Fee: '10',
+      NetworkID: 21338,
       Flags: 0,
       LastLedgerSequence: 65453019,
       Sequence: 40949322,
@@ -37,6 +38,7 @@ describe('OfferCreate', function () {
     const offer2 = {
       Account: 'r3rhWeE31Jt5sWmi4QiGLMZnY3ENgqw96W',
       Fee: '10',
+      NetworkID: 21338,
       Flags: 0,
       LastLedgerSequence: 65453019,
       Sequence: 40949322,
@@ -59,6 +61,7 @@ describe('OfferCreate', function () {
     const offer3 = {
       Account: 'r3rhWeE31Jt5sWmi4QiGLMZnY3ENgqw96W',
       Fee: '10',
+      NetworkID: 21338,
       Flags: 0,
       LastLedgerSequence: 65453019,
       Sequence: 40949322,
@@ -87,6 +90,7 @@ describe('OfferCreate', function () {
     const offer = {
       Account: 'r3rhWeE31Jt5sWmi4QiGLMZnY3ENgqw96W',
       Fee: '10',
+      NetworkID: 21338,
       Flags: 0,
       LastLedgerSequence: 65453019,
       Sequence: 40949322,
@@ -120,6 +124,7 @@ describe('OfferCreate', function () {
     const offer = {
       Account: 'r3rhWeE31Jt5sWmi4QiGLMZnY3ENgqw96W',
       Fee: '10',
+      NetworkID: 21338,
       Flags: 0,
       LastLedgerSequence: 65453019,
       Sequence: 40949322,
@@ -153,6 +158,7 @@ describe('OfferCreate', function () {
     const offer = {
       Account: 'r3rhWeE31Jt5sWmi4QiGLMZnY3ENgqw96W',
       Fee: '10',
+      NetworkID: 21338,
       Flags: 0,
       LastLedgerSequence: 65453019,
       Sequence: 40949322,
@@ -182,6 +188,7 @@ describe('OfferCreate', function () {
     const offer = {
       Account: 'r3rhWeE31Jt5sWmi4QiGLMZnY3ENgqw96W',
       Fee: '10',
+      NetworkID: 21338,
       Flags: 0,
       LastLedgerSequence: 65453019,
       Sequence: 40949322,
diff --git a/packages/xrpl/test/models/payment.test.ts b/packages/xrpl/test/models/payment.test.ts
index d0289c51..d7474a72 100644
--- a/packages/xrpl/test/models/payment.test.ts
+++ b/packages/xrpl/test/models/payment.test.ts
@@ -19,6 +19,7 @@ describe('Payment', function () {
       Destination: 'rfkE1aSy9G8Upk4JssnwBxhEv5p4mn2KTy',
       DestinationTag: 1,
       Fee: '12',
+      NetworkID: 21338,
       Flags: 2147483648,
       LastLedgerSequence: 65953073,
       Sequence: 65923914,
diff --git a/packages/xrpl/test/models/paymentChannelClaim.test.ts b/packages/xrpl/test/models/paymentChannelClaim.test.ts
index af9c9735..31458d85 100644
--- a/packages/xrpl/test/models/paymentChannelClaim.test.ts
+++ b/packages/xrpl/test/models/paymentChannelClaim.test.ts
@@ -15,6 +15,7 @@ describe('PaymentChannelClaim', function () {
     channel = {
       Account: 'rB5Ux4Lv2nRx6eeoAAsZmtctnBQ2LiACnk',
       TransactionType: 'PaymentChannelClaim',
+      NetworkID: 21338,
       Channel:
         'C1AE6DDDEEC05CF2978C0BAD6FE302948E9533691DC749DCDD3B9E5992CA6198',
       Balance: '1000000',
diff --git a/packages/xrpl/test/models/paymentChannelCreate.test.ts b/packages/xrpl/test/models/paymentChannelCreate.test.ts
index 848132ad..c9f90c7d 100644
--- a/packages/xrpl/test/models/paymentChannelCreate.test.ts
+++ b/packages/xrpl/test/models/paymentChannelCreate.test.ts
@@ -15,6 +15,7 @@ describe('PaymentChannelCreate', function () {
     channel = {
       Account: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       TransactionType: 'PaymentChannelCreate',
+      NetworkID: 21338,
       Amount: '10000',
       Destination: 'rsA2LpzuawewSBQXkiju3YQTMzW13pAAdW',
       SettleDelay: 86400,
diff --git a/packages/xrpl/test/models/paymentChannelFund.test.ts b/packages/xrpl/test/models/paymentChannelFund.test.ts
index 65c39c98..c017e6a8 100644
--- a/packages/xrpl/test/models/paymentChannelFund.test.ts
+++ b/packages/xrpl/test/models/paymentChannelFund.test.ts
@@ -15,6 +15,7 @@ describe('PaymentChannelFund', function () {
     channel = {
       Account: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       TransactionType: 'PaymentChannelFund',
+      NetworkID: 21338,
       Channel:
         'C1AE6DDDEEC05CF2978C0BAD6FE302948E9533691DC749DCDD3B9E5992CA6198',
       Amount: '200000',
diff --git a/packages/xrpl/test/models/setRegularKey.test.ts b/packages/xrpl/test/models/setRegularKey.test.ts
index 1dcb8598..4421af32 100644
--- a/packages/xrpl/test/models/setRegularKey.test.ts
+++ b/packages/xrpl/test/models/setRegularKey.test.ts
@@ -16,6 +16,7 @@ describe('SetRegularKey', function () {
       TransactionType: 'SetRegularKey',
       Account: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       Fee: '12',
+      NetworkID: 21338,
       Flags: 0,
       RegularKey: 'rAR8rR8sUkBoCZFawhkWzY4Y5YoyuznwD',
     } as any
diff --git a/packages/xrpl/test/models/signerListSet.test.ts b/packages/xrpl/test/models/signerListSet.test.ts
index d99062c5..9a1fbeb3 100644
--- a/packages/xrpl/test/models/signerListSet.test.ts
+++ b/packages/xrpl/test/models/signerListSet.test.ts
@@ -17,6 +17,7 @@ describe('SignerListSet', function () {
       TransactionType: 'SignerListSet',
       Account: 'rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn',
       Fee: '12',
+      NetworkID: 21338,
       SignerQuorum: 3,
       SignerEntries: [
         {
diff --git a/packages/xrpl/test/models/ticketCreate.test.ts b/packages/xrpl/test/models/ticketCreate.test.ts
index 4ec21a8b..5ee22578 100644
--- a/packages/xrpl/test/models/ticketCreate.test.ts
+++ b/packages/xrpl/test/models/ticketCreate.test.ts
@@ -15,6 +15,7 @@ describe('TicketCreate', function () {
     ticketCreate = {
       TransactionType: 'TicketCreate',
       Account: 'rUn84CUYbNjRoTQ6mSW7BVJPSVJNLb1QLo',
+      NetworkID: 21338,
       TicketCount: 150,
     } as any
   })
diff --git a/packages/xrpl/test/models/trustSet.test.ts b/packages/xrpl/test/models/trustSet.test.ts
index 81fa347e..5310b5f1 100644
--- a/packages/xrpl/test/models/trustSet.test.ts
+++ b/packages/xrpl/test/models/trustSet.test.ts
@@ -15,6 +15,7 @@ describe('TrustSet', function () {
     trustSet = {
       TransactionType: 'TrustSet',
       Account: 'rUn84CUYbNjRoTQ6mSW7BVJPSVJNLb1QLo',
+      NetworkID: 21338,
       LimitAmount: {
         currency: 'XRP',
         issuer: 'rcXY84C4g14iFp6taFXjjQGVeHqSCh9RX',
diff --git a/packages/xrpl/test/models/utils.test.ts b/packages/xrpl/test/models/utils.test.ts
index b2eb9343..405ff605 100644
--- a/packages/xrpl/test/models/utils.test.ts
+++ b/packages/xrpl/test/models/utils.test.ts
@@ -50,6 +50,7 @@ describe('Models Utils', function () {
       const tx: OfferCreate = {
         Account: 'r3rhWeE31Jt5sWmi4QiGLMZnY3ENgqw96W',
         Fee: '10',
+        NetworkID: 21338,
         TakerGets: {
           currency: 'DSH',
           issuer: 'rcXY84C4g14iFp6taFXjjQGVeHqSCh9RX',