diff --git a/Source/kwsys/testDynamicLoader.cxx b/Source/kwsys/testDynamicLoader.cxx
index 40e426e8c..ea50c1fda 100644
--- a/Source/kwsys/testDynamicLoader.cxx
+++ b/Source/kwsys/testDynamicLoader.cxx
@@ -15,6 +15,7 @@
 
 #include KWSYS_HEADER(DynamicLoader.hxx)
 #include KWSYS_HEADER(ios/iostream)
+#include KWSYS_HEADER(stl/string)
 
 // Work-around CMake dependency scanning limitation.  This must
 // duplicate the above list of headers.