diff --git a/upb/decode.c b/upb/decode.c
index 2d5bb49525..744b235aee 100644
--- a/upb/decode.c
+++ b/upb/decode.c
@@ -905,7 +905,7 @@ static const char* decode_known(upb_Decoder* d, const char* ptr,
     const upb_MiniTable_Extension* ext_layout =
         (const upb_MiniTable_Extension*)field;
     upb_Message_Extension* ext =
-        _upb_Message_Getorcreateext(msg, ext_layout, &d->arena);
+        _upb_Message_GetOrCreateExtension(msg, ext_layout, &d->arena);
     if (UPB_UNLIKELY(!ext)) return decode_err(d, kUpb_DecodeStatus_OutOfMemory);
     msg = &ext->data;
     subs = &ext->ext->sub;
diff --git a/upb/msg.c b/upb/msg.c
index b8a629467d..46738ca1fb 100644
--- a/upb/msg.c
+++ b/upb/msg.c
@@ -153,7 +153,7 @@ void _upb_Message_Clearext(upb_Message* msg,
   }
 }
 
-upb_Message_Extension* _upb_Message_Getorcreateext(
+upb_Message_Extension* _upb_Message_GetOrCreateExtension(
     upb_Message* msg, const upb_MiniTable_Extension* e, upb_Arena* arena) {
   upb_Message_Extension* ext =
       (upb_Message_Extension*)_upb_Message_Getext(msg, e);
diff --git a/upb/msg_internal.h b/upb/msg_internal.h
index 8eb7dc7bf3..15441997dd 100644
--- a/upb/msg_internal.h
+++ b/upb/msg_internal.h
@@ -324,7 +324,7 @@ typedef struct {
 /* Adds the given extension data to the given message. |ext| is copied into the
  * message instance. This logically replaces any previously-added extension with
  * this number */
-upb_Message_Extension* _upb_Message_Getorcreateext(
+upb_Message_Extension* _upb_Message_GetOrCreateExtension(
     upb_Message* msg, const upb_MiniTable_Extension* ext, upb_Arena* arena);
 
 /* Returns an array of extensions for this message. Note: the array is
diff --git a/upb/reflection.c b/upb/reflection.c
index a3a64d2780..31c487b230 100644
--- a/upb/reflection.c
+++ b/upb/reflection.c
@@ -202,7 +202,7 @@ make:
 bool upb_Message_Set(upb_Message* msg, const upb_FieldDef* f,
                      upb_MessageValue val, upb_Arena* a) {
   if (upb_FieldDef_IsExtension(f)) {
-    upb_Message_Extension* ext = _upb_Message_Getorcreateext(
+    upb_Message_Extension* ext = _upb_Message_GetOrCreateExtension(
         msg, _upb_FieldDef_ExtensionMiniTable(f), a);
     if (!ext) return false;
     memcpy(&ext->data, &val, sizeof(val));
diff --git a/upbc/protoc-gen-upb.cc b/upbc/protoc-gen-upb.cc
index ce13a7a525..7250a56dd6 100644
--- a/upbc/protoc-gen-upb.cc
+++ b/upbc/protoc-gen-upb.cc
@@ -776,7 +776,7 @@ void GenerateExtensionInHeader(const protobuf::FieldDescriptor* ext,
         R"cc(
           UPB_INLINE void $1_set_$2(struct $3* msg, $0 ext, upb_Arena* arena) {
             const upb_Message_Extension* msg_ext =
-                _upb_Message_Getorcreateext(msg, &$4, arena);
+                _upb_Message_GetOrCreateExtension(msg, &$4, arena);
             UPB_ASSERT(msg_ext);
             *UPB_PTR_AT(&msg_ext->data, 0, $0) = ext;
           }