diff --git a/tests/requirements/base.txt b/tests/requirements/base.txt
index 6ee885e13c..08a6b3a526 100644
--- a/tests/requirements/base.txt
+++ b/tests/requirements/base.txt
@@ -4,7 +4,7 @@ docutils
 geoip2
 jinja2 >= 2.9.2
 numpy
-Pillow
+Pillow != 5.4.0
 PyYAML
 # pylibmc/libmemcached can't be built on Windows.
 pylibmc; sys.platform != 'win32'