diff --git a/test/Unit/lit.cfg b/test/Unit/lit.cfg
index a41f0937f9a..35092964a5c 100644
--- a/test/Unit/lit.cfg
+++ b/test/Unit/lit.cfg
@@ -21,6 +21,13 @@ if llvm_obj_root is not None:
 llvm_build_mode = getattr(config, 'llvm_build_mode', "Debug")
 config.test_format = lit.formats.GoogleTest(llvm_build_mode, 'Tests')
 
+# Propagate the temp directory. Windows requires this because it uses \Windows\
+# if none of these are present.
+if 'TMP' in os.environ:
+    config.environment['TMP'] = os.environ['TMP']
+if 'TEMP' in os.environ:
+    config.environment['TEMP'] = os.environ['TEMP']
+
 ###
 
 # If necessary, point the dynamic loader at libLLVM.so.
diff --git a/test/lit.cfg b/test/lit.cfg
index 63b00325f3e..8c869f0787b 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -58,6 +58,13 @@ if 'INCLUDE' in os.environ:
 if 'LIB' in os.environ:
     config.environment['LIB'] = os.environ['LIB']
 
+# Propagate the temp directory. Windows requires this because it uses \Windows\
+# if none of these are present.
+if 'TMP' in os.environ:
+    config.environment['TMP'] = os.environ['TMP']
+if 'TEMP' in os.environ:
+    config.environment['TEMP'] = os.environ['TEMP']
+
 # Propagate LLVM_SRC_ROOT into the environment.
 config.environment['LLVM_SRC_ROOT'] = getattr(config, 'llvm_src_root', '')