diff --git a/ext/liquid/tokenizer.c b/ext/liquid/tokenizer.c
index fa260df..26e2368 100644
--- a/ext/liquid/tokenizer.c
+++ b/ext/liquid/tokenizer.c
@@ -26,6 +26,7 @@ static VALUE rb_initialize(VALUE self, VALUE source)
     Data_Get_Struct(self, struct liquid_tokenizer, tokenizer);
     tokenizer->cursor = RSTRING_PTR(source);
     tokenizer->length = RSTRING_LEN(source);
+    return Qnil;
 }
 
 void liquid_tokenizer_next(struct liquid_tokenizer *tokenizer, struct token *token)