diff --git a/include/geos/geom/CoordinateSequenceFilter.h b/include/geos/geom/CoordinateSequenceFilter.h
index cb92435586..481255cf97 100644
--- a/include/geos/geom/CoordinateSequenceFilter.h
+++ b/include/geos/geom/CoordinateSequenceFilter.h
@@ -21,6 +21,7 @@
 #include <geos/export.h>
 
 #include <cassert>
+#include <cstddef>
 
 // Forward declarations
 namespace geos {