diff --git a/kitty/child.c b/kitty/child.c
index 6df761523..31e78ad7a 100644
--- a/kitty/child.c
+++ b/kitty/child.c
@@ -32,7 +32,7 @@ serialize_string_tuple(PyObject *src) {
 static inline void
 free_string_tuple(char** data) {
     size_t i = 0;
-	while(data[i++]) free(data[i-1]);
+	while(data[i]) free(data[i++]);
 	free(data);
 }