diff --git a/src/libxrpl/tx/transactors/system/Batch.cpp b/src/libxrpl/tx/transactors/system/Batch.cpp
index 612451c764..1c4486df14 100644
--- a/src/libxrpl/tx/transactors/system/Batch.cpp
+++ b/src/libxrpl/tx/transactors/system/Batch.cpp
@@ -408,7 +408,6 @@ Batch::preflightSigValidated(PreflightContext const& ctx)
     }
 
     // Validation Batch Signers
-    std::unordered_set<AccountID> batchSigners;
     if (ctx.tx.isFieldPresent(sfBatchSigners))
     {
         STArray const& signers = ctx.tx.getFieldArray(sfBatchSigners);
@@ -421,11 +420,8 @@ Batch::preflightSigValidated(PreflightContext const& ctx)
             return temARRAY_TOO_LARGE;
         }
 
-        // Add batch signers to the set to ensure all signer accounts are
-        // unique. Meanwhile, remove signer accounts from the set of inner
-        // transaction accounts (`requiredSigners`). By the end of the loop,
-        // `requiredSigners` should be empty, indicating that all inner
-        // accounts are matched with signers.
+        // Batch signers must be in strictly ascending order by AccountID.
+        AccountID lastBatchSigner(beast::zero);
         for (auto const& signer : signers)
         {
             AccountID const signerAccount = signer.getAccountID(sfAccount);
@@ -436,13 +432,21 @@ Batch::preflightSigValidated(PreflightContext const& ctx)
                 return temBAD_SIGNER;
             }
 
-            if (!batchSigners.insert(signerAccount).second)
+            if (lastBatchSigner == signerAccount)
             {
                 JLOG(ctx.j.debug()) << "BatchTrace[" << parentBatchId << "]: "
                                     << "duplicate signer found: " << signerAccount;
-                return temREDUNDANT;
+                return temBAD_SIGNER;
             }
 
+            if (lastBatchSigner > signerAccount)
+            {
+                JLOG(ctx.j.debug()) << "BatchTrace[" << parentBatchId << "]: "
+                                    << "unsorted signers array: " << signerAccount;
+                return temBAD_SIGNER;
+            }
+            lastBatchSigner = signerAccount;
+
             // Check that the batch signer is in the required signers set.
             // Remove it if it does, as it can be crossed off the list.
             if (requiredSigners.erase(signerAccount) == 0)
diff --git a/src/test/app/Batch_test.cpp b/src/test/app/Batch_test.cpp
index 25f0bb9d20..9d72bc84e2 100644
--- a/src/test/app/Batch_test.cpp
+++ b/src/test/app/Batch_test.cpp
@@ -522,7 +522,7 @@ class Batch_test : public beast::unit_test::suite
             env.close();
         }
 
-        // temREDUNDANT: Batch: duplicate signer found
+        // temBAD_SIGNER: Batch: duplicate signer (caught by ascending order check)
         {
             auto const seq = env.seq(alice);
             auto const batchFee = batch::calcBatchFee(env, 2, 2);
@@ -530,7 +530,7 @@ class Batch_test : public beast::unit_test::suite
                 batch::inner(pay(alice, bob, XRP(10)), seq + 1),
                 batch::inner(pay(bob, alice, XRP(5)), env.seq(bob)),
                 batch::sig(bob, bob),
-                ter(temREDUNDANT));
+                ter(temBAD_SIGNER));
             env.close();
         }
 
@@ -4459,6 +4459,41 @@ class Batch_test : public beast::unit_test::suite
         }
     }
 
+    void
+    testUnsortedBatchSigners(FeatureBitset features)
+    {
+        testcase("unsorted batch signers");
+
+        using namespace test::jtx;
+
+        Env env{*this, features};
+
+        auto const alice = Account("alice");
+        auto const bob = Account("bob");
+        auto const carol = Account("carol");
+        env.fund(XRP(10000), alice, bob, carol);
+        env.close();
+
+        auto const seq = env.seq(alice);
+        auto const bobSeq = env.seq(bob);
+        auto const carolSeq = env.seq(carol);
+        auto const batchFee = batch::calcBatchFee(env, 2, 2);
+
+        auto jt = env.jt(
+            batch::outer(alice, seq, batchFee, tfAllOrNothing),
+            batch::inner(pay(bob, alice, XRP(10)), bobSeq),
+            batch::inner(pay(carol, alice, XRP(5)), carolSeq),
+            batch::sig(bob, carol));
+
+        auto const s0 = jt.jv[sfBatchSigners.jsonName][0u];
+        auto const s1 = jt.jv[sfBatchSigners.jsonName][1u];
+        jt.jv[sfBatchSigners.jsonName][0u] = s1;
+        jt.jv[sfBatchSigners.jsonName][1u] = s0;
+
+        env(jt.jv, ter(temBAD_SIGNER));
+        env.close();
+    }
+
     void
     testWithFeats(FeatureBitset features)
     {
@@ -4494,6 +4529,7 @@ class Batch_test : public beast::unit_test::suite
         testValidateRPCResponse(features);
         testBatchCalculateBaseFee(features);
         testStandaloneInnerBatchFlag(features);
+        testUnsortedBatchSigners(features);
     }
 
 public: