diff --git a/test-requirements.txt b/test-requirements.txt
index 5afaa74bf..b6d3057dd 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -22,7 +22,7 @@ qpid-python
 redis>=2.10.0
 
 # for test_impl_zmq
-pyzmq>=14.3.1
+pyzmq>=14.3.1 # LGPL+BSD
 
 # when we can require tox>= 1.4, this can go into tox.ini:
 #  [testenv:cover]