diff --git a/runtests.rst b/runtests.rst
--- a/runtests.rst
+++ b/runtests.rst
@@ -6,9 +6,10 @@
 .. note::
 
     This document assumes you are working from an
-    :ref:`in-development <indevbranch>` checkout of Python. If you
-    are not then some things presented here may not work as they may depend
-    on new features not available in earlier versions of Python.
+    :ref:`in-development <indevbranch>` checkout of Python. Some features
+    presented here may not work or be available in earlier versions of
+    Python.  See the :ref:`Python 2.7 <runtests27>` section for a
+    discussion of some of these differences.
 
 Running
 -------
@@ -89,6 +90,21 @@
 settings on some platforms will disallow some tests)
 
 
+.. _runtests27:
+
+Python 2.7
+^^^^^^^^^^
+
+This section describes some differences in the test harness when using
+Python 2.7.  To run tests from Python 2.7, use the following as the
+base command instead of the one described above: ::
+
+    ./python -m test.regrtest
+
+Many of the options discussed above will still work with this modified
+command.
+
+
 Writing
 -------