diff --git a/php/ext/google/protobuf/php-upb.h b/php/ext/google/protobuf/php-upb.h
index 00303e5fe5..ae22247b56 100644
--- a/php/ext/google/protobuf/php-upb.h
+++ b/php/ext/google/protobuf/php-upb.h
@@ -2608,32 +2608,6 @@ UPB_INLINE void _upb_Message_GetExtensionField(
   }
 }
 
-// Gets a extension message or creates a default message and sets the extension
-// if it doesn't already exist.
-UPB_INLINE bool _upb_Message_GetOrCreateExtensionSubmessage(
-    struct upb_Message* msg, const upb_MiniTableExtension* mt_ext,
-    struct upb_Message** val, upb_Arena* a) {
-  const upb_MiniTableField* f = &mt_ext->UPB_PRIVATE(field);
-  UPB_ASSUME(upb_MiniTableField_IsExtension(f));
-  const struct upb_Extension* const_ext = _upb_Message_Getext(msg, mt_ext);
-  if (const_ext) {
-    // Extension exists, get a mutable version of it.
-    struct upb_Extension* ext =
-        _upb_Message_GetOrCreateExtension(msg, mt_ext, a);
-    *val = (struct upb_Message*)ext->data.ptr;
-    return true;
-  }
-  // Extension doesn't exist, create a new message and set it.
-  struct upb_Message* ext_msg =
-      _upb_Message_New(upb_MiniTableExtension_GetSubMessage(mt_ext), a);
-  if (!ext_msg) return false;
-  struct upb_Extension* ext = _upb_Message_GetOrCreateExtension(msg, mt_ext, a);
-  if (!ext) return false;
-  ext->data.ptr = ext_msg;
-  *val = ext_msg;
-  return true;
-}
-
 UPB_INLINE void _upb_Message_SetNonExtensionField(
     struct upb_Message* msg, const upb_MiniTableField* field, const void* val) {
   UPB_ASSUME(!upb_MiniTableField_IsExtension(field));
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.h b/ruby/ext/google/protobuf_c/ruby-upb.h
index 584acf1ead..433d25c131 100755
--- a/ruby/ext/google/protobuf_c/ruby-upb.h
+++ b/ruby/ext/google/protobuf_c/ruby-upb.h
@@ -2610,32 +2610,6 @@ UPB_INLINE void _upb_Message_GetExtensionField(
   }
 }
 
-// Gets a extension message or creates a default message and sets the extension
-// if it doesn't already exist.
-UPB_INLINE bool _upb_Message_GetOrCreateExtensionSubmessage(
-    struct upb_Message* msg, const upb_MiniTableExtension* mt_ext,
-    struct upb_Message** val, upb_Arena* a) {
-  const upb_MiniTableField* f = &mt_ext->UPB_PRIVATE(field);
-  UPB_ASSUME(upb_MiniTableField_IsExtension(f));
-  const struct upb_Extension* const_ext = _upb_Message_Getext(msg, mt_ext);
-  if (const_ext) {
-    // Extension exists, get a mutable version of it.
-    struct upb_Extension* ext =
-        _upb_Message_GetOrCreateExtension(msg, mt_ext, a);
-    *val = (struct upb_Message*)ext->data.ptr;
-    return true;
-  }
-  // Extension doesn't exist, create a new message and set it.
-  struct upb_Message* ext_msg =
-      _upb_Message_New(upb_MiniTableExtension_GetSubMessage(mt_ext), a);
-  if (!ext_msg) return false;
-  struct upb_Extension* ext = _upb_Message_GetOrCreateExtension(msg, mt_ext, a);
-  if (!ext) return false;
-  ext->data.ptr = ext_msg;
-  *val = ext_msg;
-  return true;
-}
-
 UPB_INLINE void _upb_Message_SetNonExtensionField(
     struct upb_Message* msg, const upb_MiniTableField* field, const void* val) {
   UPB_ASSUME(!upb_MiniTableField_IsExtension(field));