diff --git a/tox.ini b/tox.ini
index f26cc12..590edf9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,7 +9,9 @@ setenv =
     PYLAST_API_KEY={env:PYLAST_API_KEY:}
     PYLAST_API_SECRET={env:PYLAST_API_SECRET:}
 deps =
-     pyyaml
+    # Workaround for yaml/pyyaml#126
+     py27,py36,py35,py34,pypy,pypy3,py36dev: pyyaml
+     py37dev: git+https://github.com/yaml/pyyaml@master#egg=pyyaml
      pytest
      mock
      ipdb