diff --git a/src/widgets/GraphGridLayout.cpp b/src/widgets/GraphGridLayout.cpp
index 55c61ed0..9c66f0d1 100644
--- a/src/widgets/GraphGridLayout.cpp
+++ b/src/widgets/GraphGridLayout.cpp
@@ -4,6 +4,7 @@
 #include <unordered_map>
 #include <queue>
 #include <stack>
+#include <cassert>
 
 // Vector functions
 template<class T>