diff --git a/src/V3SplitVar.cpp b/src/V3SplitVar.cpp
index 3ac301fba..80702ec74 100644
--- a/src/V3SplitVar.cpp
+++ b/src/V3SplitVar.cpp
@@ -122,6 +122,7 @@
 #include "V3Stats.h"
 
 #include <algorithm>  // sort
+#include <map>
 #include <set>
 #include <vector>
 #include VL_INCLUDE_UNORDERED_MAP