diff --git a/src/strings.c b/src/strings.c
index e905da2..5246077 100644
--- a/src/strings.c
+++ b/src/strings.c
@@ -81,6 +81,7 @@ apfl_string_move(struct apfl_string *src)
 {
     struct apfl_string out = *src;
     src->bytes = NULL;
+    src->len = 0;
     return out;
 }