diff --git a/src/THcShowerHit.h b/src/THcShowerHit.h
index 7619fb081b27e7a04e204f71cce4ae274977c992..41bfd17c24d4068d3ad8fd8a5961feb858ba9d03 100644
--- a/src/THcShowerHit.h
+++ b/src/THcShowerHit.h
@@ -7,6 +7,7 @@
 #include <iterator>
 #include <iostream>
 #include <memory>
+#include <vector>
 #include "TMath.h"
 
 using namespace std;