diff --git a/requirements.txt b/requirements.txt
index 1da37ceca..6cdb564ed 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -37,6 +37,7 @@ pathlib2>=2.3.0
 Pillow>=3.0
 pyang>=1.7.2,<2.0
 pyflakes>=0.9.2
+pyopenssl>=17.5.0		# Used by urllib3.contrib, which is used by PyQuery but not marked as a dependency
 pyquery>=1.2.13,!=1.2.14	# Pyqyery 1.2.14 fails on some selectors or stacked selectors
 python-dateutil>=2.2
 python-magic>=0.4.6