diff --git a/folly/wangle/rx/Observable.h b/folly/wangle/rx/Observable.h
index b3f2556..95b60bf 100644
--- a/folly/wangle/rx/Observable.h
+++ b/folly/wangle/rx/Observable.h
@@ -25,6 +25,7 @@
 #include <folly/ThreadLocal.h>
 #include <folly/small_vector.h>
 #include <folly/Executor.h>
+#include <folly/Memory.h>
 #include <map>
 #include <memory>