diff --git a/kghostview/kgvdocument.cpp b/kghostview/kgvdocument.cpp
index ec70944d..8a1a6776 100644
--- a/kghostview/kgvdocument.cpp
+++ b/kghostview/kgvdocument.cpp
@@ -17,6 +17,7 @@
  */
 
 #include <algorithm>
+#include <functional>
 #include <memory>
 
 #include <tqfileinfo.h>