diff --git a/include/xrpl/protocol/Rules.h b/include/xrpl/protocol/Rules.h
index 767a63be06..4b2631cdd8 100644
--- a/include/xrpl/protocol/Rules.h
+++ b/include/xrpl/protocol/Rules.h
@@ -23,7 +23,7 @@ isFeatureEnabled(uint256 const& feature, bool resultIfNoRules);
  * Returns false if no global Rules object is available. i.e. Outside of
  * a Transactor context
  */
-bool
+inline bool
 isFeatureEnabled(uint256 const& feature)
 {
     return isFeatureEnabled(feature, false);