diff --git a/example/example2.cpp b/example/example2.cpp
index 08fdd06..c4a352e 100644
--- a/example/example2.cpp
+++ b/example/example2.cpp
@@ -9,6 +9,7 @@
 */
 
 #include "example.h"
+#include <pybind/stl.h>
 
 class Example2 {
 public: