diff --git a/ccutil/unicharcompress.cpp b/ccutil/unicharcompress.cpp
index f162fbd5715f099792410fa72c61967ad35923ca..064207cf29199d59979694415c5a3807249c23a8 100644
--- a/ccutil/unicharcompress.cpp
+++ b/ccutil/unicharcompress.cpp
@@ -21,6 +21,7 @@
 
 #include "unicharcompress.h"
 #include <memory>
+#include <algorithm>
 #include "tprintf.h"
 
 namespace tesseract {