diff --git a/test-requirements.txt b/test-requirements.txt
index db24cc0cea..fbc00b8bdc 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -21,3 +21,5 @@ lxml>=2.3,!=3.7.0  # BSD
 # For translations
 # Babel 2.4.0 is broken, fixed in 2.4.1
 Babel>=2.3.4,!=2.4.0  # BSD
+
+Pillow>=2.4.0,<4.2.0  # PIL License