diff --git a/upb/mini_table/internal/field.h b/upb/mini_table/internal/field.h
index d1ee25b156..f4961fc202 100644
--- a/upb/mini_table/internal/field.h
+++ b/upb/mini_table/internal/field.h
@@ -154,7 +154,7 @@ UPB_API_INLINE bool upb_MiniTableField_IsClosedEnum(
   return f->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Enum;
 }
 
-UPB_INLINE bool upb_MiniTableField_IsInOneof(
+UPB_API_INLINE bool upb_MiniTableField_IsInOneof(
     const struct upb_MiniTableField* f) {
   return f->presence < 0;
 }