diff --git a/tox.ini b/tox.ini
index bffdb2df..ad43d9ec 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,11 +6,13 @@ sitepackages = true
 commands =
     py.test \
         --basetemp={envtmpdir} \
-        --junit-xml=xunit-{envname}.xml --cov=mopidy
+        --junit-xml=xunit-{envname}.xml --cov=mopidy \
+        {posargs}
 deps =
     mock
     pytest
     pytest-cov
+    pytest-xdist
 
 [testenv:py27-tornado23]
 commands = py.test tests/http