diff --git a/Adapter.hxx b/Adapter.hxx
index a778950..fb6e51c 100644
--- a/Adapter.hxx
+++ b/Adapter.hxx
@@ -2,6 +2,7 @@
 
 #include <thread>
 #include "locked_queue.hh"
+#include <cassert>
 
 
 namespace pEp {