diff --git a/quic/core/quic_stream_sequencer.h b/quic/core/quic_stream_sequencer.h
index 8f8a6a0..54e0e28 100644
--- a/quic/core/quic_stream_sequencer.h
+++ b/quic/core/quic_stream_sequencer.h
@@ -25,7 +25,7 @@
 class QUIC_EXPORT_PRIVATE QuicStreamSequencer {
  public:
   // Interface that thie Sequencer uses to communicate with the Stream.
-  class StreamInterface {
+  class QUIC_EXPORT_PRIVATE StreamInterface {
    public:
     virtual ~StreamInterface() = default;