diff --git a/flang/runtime/namelist.cpp b/flang/runtime/namelist.cpp
--- a/flang/runtime/namelist.cpp
+++ b/flang/runtime/namelist.cpp
@@ -329,7 +329,7 @@
     }
   } else {
     handler.SignalError("NAMELIST component reference of input group item %s "
-                        "has no name after '%'",
+                        "has no name after '%%'",
         name);
   }
   return false;