diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 314bafd1e7d..54c1343e2a5 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -1019,7 +1019,7 @@ static PyMethodDef deque_methods[] = {
 };
 
 PyDoc_STRVAR(deque_doc,
-"deque(iterable[, maxlen]) --> deque object\n\
+"deque([iterable[, maxlen]]) --> deque object\n\
 \n\
 Build an ordered collection with optimized access from its endpoints.");