diff --git a/python-requests-mock.spec b/python-requests-mock.spec
index 3514394..ee2d8fb 100644
--- a/python-requests-mock.spec
+++ b/python-requests-mock.spec
@@ -40,6 +40,7 @@ BuildRequires:  python3-dbm
 BuildRequires:  fdupes
 Requires:       python-requests >= 2.3
 Requires:       python-six
+Requires:       python-urllib3 < 2
 BuildArch:      noarch
 Requires:       python-dbm
 %python_subpackages