diff --git a/requirements.txt b/requirements.txt
index ae6769a..cff7fd8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,6 +7,11 @@ lockfile
 python-daemon<2.0
 extras
 GitPython>=0.3.2.RC1
+# NOTE(tonyb) Pillow isn't directly needed but it's pulled in via
+# Collecting Pillow (from blockdiag>=1.5.0->sphinxcontrib-blockdiag>=0.5.5
+# So cap as per global-requirements until https://launchpad.net/bugs/1501995
+# is properly fixed
+Pillow>=2.4.0,<3.0.0 # MIT
 sphinxcontrib-programoutput
 sphinxcontrib-seqdiag