diff --git a/extras/fixture/src/unity_fixture.c b/extras/fixture/src/unity_fixture.c
index 1e0aa37a81dd4e4bfa431746393b21bdb7d31348..5dc099c6d614e51bac6d088d4764c082b22ab6a9 100644
--- a/extras/fixture/src/unity_fixture.c
+++ b/extras/fixture/src/unity_fixture.c
@@ -164,8 +164,8 @@ void UnityMalloc_MakeMallocFailAfterCount(int countdown)
 
 typedef struct GuardBytes
 {
-    int size;
-    char guard[sizeof(int)];
+    size_t size;
+    char guard[sizeof(size_t)];
 } Guard;