diff --git a/src/load.c b/src/load.c
index 340b748..2c7b71e 100644
--- a/src/load.c
+++ b/src/load.c
@@ -701,7 +701,7 @@ static json_t *parse_object(lex_t *lex, size_t flags, json_error_t *error)
             return NULL;
         if (memchr(key, len, '\0')) {
             jsonp_free(key);
-            error_set(error, lex, "nul char in object key not supported");
+            error_set(error, lex, "NUL byte in object key not supported");
             goto error;
         }