diff --git a/tests/unit/requirements.txt b/tests/unit/requirements.txt
index 8d2d692333..0e75160493 100644
--- a/tests/unit/requirements.txt
+++ b/tests/unit/requirements.txt
@@ -20,5 +20,6 @@ openshift ; python_version >= '2.7'
 ruamel.yaml.clib <= 0.2.2 ; python_version == '2.7' # 0.2.4 require python 3.5 or later, 0.2.3 is yanked
 
 # requirement for maven_artifact module
-lxml
+lxml < 4.3.0 ; python_version < '2.7' # lxml 4.3.0 and later require python 2.7 or later
+lxml ; python_version >= '2.7'
 semantic_version