diff --git a/http2/adapter/oghttp2_session.h b/http2/adapter/oghttp2_session.h
index aac2688..a64eea2 100644
--- a/http2/adapter/oghttp2_session.h
+++ b/http2/adapter/oghttp2_session.h
@@ -478,7 +478,7 @@
       std::numeric_limits<uint32_t>::max();
   uint32_t max_inbound_concurrent_streams_ =
       std::numeric_limits<uint32_t>::max();
-  Options options_;
+  const Options options_;
 
   // The HPACK encoder header table capacity that will be applied when
   // acking SETTINGS from the peer. Only contains a value if the peer advertises