diff --git a/setup.py b/setup.py
index 877de94fae..acbf73cc8f 100755
--- a/setup.py
+++ b/setup.py
@@ -13,6 +13,9 @@ def check_version_info():
     vi = sys.version_info
     if vi[0] == 2 and vi[1:3] >= (7, 9):
         return
+    if vi.major > 2 and 'CALIBRE_PY3_PORT' in os.environ:
+        # PY3_TODO: Remove check for 'CALIBRE_PY3_PORT' once calibre works with python3
+        return
     raise SystemExit(
         'calibre requires python >= 2.7.9 and < 3. Current python version: %s'
         % vi)