diff --git a/site_scons/gem5_scons/defaults.py b/site_scons/gem5_scons/defaults.py
index f800b6755c..944f7e5da6 100644
--- a/site_scons/gem5_scons/defaults.py
+++ b/site_scons/gem5_scons/defaults.py
@@ -52,6 +52,7 @@ def EnvDefaults(env):
             "CC",
             "CXX",
             "HOME",
+            "CPATH",
             "LD_LIBRARY_PATH",
             "LIBRARY_PATH",
             "PATH",