diff --git a/include/rapidjson/document.h b/include/rapidjson/document.h
index 6275f96..0a5a7b2 100644
--- a/include/rapidjson/document.h
+++ b/include/rapidjson/document.h
@@ -1887,7 +1887,8 @@ public:
     template <unsigned parseFlags, typename SourceEncoding, typename InputStream>
     GenericDocument& ParseStream(InputStream& is) {
         ValueType::SetNull(); // Remove existing root if exist
-        GenericReader<SourceEncoding, Encoding, StackAllocator> reader(&stack_.GetAllocator());
+        GenericReader<SourceEncoding, Encoding, StackAllocator> reader(
+            stack_.HasAllocator() ? &stack_.GetAllocator() : 0);
         ClearStackOnExit scope(*this);
         parseResult_ = reader.template Parse<parseFlags>(is, *this);
         if (parseResult_) {