diff --git a/_pytest/pytester.py b/_pytest/pytester.py
index fb8adc50a..3ec8b696e 100644
--- a/_pytest/pytester.py
+++ b/_pytest/pytester.py
@@ -516,6 +516,8 @@ class TmpTestdir:
         pexpect = py.test.importorskip("pexpect", "2.4")
         if hasattr(sys, 'pypy_version_info') and '64' in py.std.platform.machine():
             pytest.skip("pypy-64 bit not supported")
+        if sys.platform == "darwin":
+            pytest.xfail("pexpect does not work reliably on darwin?!")
         logfile = self.tmpdir.join("spawn.out")
         child = pexpect.spawn(cmd, logfile=logfile.open("w"))
         child.timeout = expect_timeout