diff --git a/Lib/tempfile.py b/Lib/tempfile.py
index eae528d..eb66590 100644
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -284,6 +284,8 @@ def mkdtemp(suffix="", prefix=template, dir=None):
 
     if dir is None:
         dir = gettempdir()
+    else:
+        dir = _os.path.abspath(dir)
 
     names = _get_candidate_names()
 
diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py
index 351ef08..fa9f15b 100644
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -1220,6 +1220,19 @@ class TestTemporaryDirectory(BaseTestCase):
             self.assertEqual(name, d.name)
         self.assertFalse(os.path.exists(name))
 
+    def test_different_cwd_upon_creation(self): # See issue #20267
+        # Relative paths are supported
+        old_cwd = os.getcwd()
+        try:
+            new_cwd = os.path.dirname(tempfile.mkdtemp())
+            os.chdir(new_cwd)
+            d = self.do_create(dir='.')
+        finally:
+            os.chdir(old_cwd)
+
+        self.assertTrue(new_cwd in d.name)
+        d.cleanup()
+
 
 def test_main():
     support.run_unittest(__name__)