diff --git a/Rez/RezLexerNextToken.cc b/Rez/RezLexerNextToken.cc
index fb69bd21b0..8cc46681ec 100644
--- a/Rez/RezLexerNextToken.cc
+++ b/Rez/RezLexerNextToken.cc
@@ -2,6 +2,7 @@
 #include "RezLexerWaveToken.h"
 #include "RezParser.generated.hh"
 #include <unordered_map>
+#include <sstream>
 
 #include <boost/regex.hpp>