diff --git a/include/fxos/semantics.h b/include/fxos/semantics.h
index 1f7090c..631da14 100644
--- a/include/fxos/semantics.h
+++ b/include/fxos/semantics.h
@@ -23,6 +23,7 @@
 #include <memory>
 #include <variant>
 #include <algorithm>
+#include <vector>
 
 namespace FxOS {