diff --git a/Modules/_json.c b/Modules/_json.c
index f574004b38e..07bcd318b1e 100644
--- a/Modules/_json.c
+++ b/Modules/_json.c
@@ -18,7 +18,7 @@ static PyTypeObject PyEncoderType;
 
 typedef struct _PyScannerObject {
     PyObject_HEAD
-    char strict;
+    signed char strict;
     PyObject *object_hook;
     PyObject *object_pairs_hook;
     PyObject *parse_float;