diff --git a/dev_requirements.txt b/dev_requirements.txt
--- a/dev_requirements.txt
+++ b/dev_requirements.txt
@@ -2,6 +2,6 @@ pytest>=2.7.0,<3.0
 pytest-runner
 pytest-sugar>=0.7.0,<1.0.0
 pytest-catchlog
-webtest==1.4.3
+WebTest<2 # this is also a Pylons dependency and pinned in setup.py to avoid version conflicts for WebOb
 mock
 sphinx
diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -39,6 +39,7 @@ requirements = [
     "waitress>=0.8.8,<1.0",
     "webob>=1.0.8,<=1.1.1",
     "Pylons>=1.0.0,<=1.0.2",
+    "WebTest<2.0", # make the Pylons dependency pick a version that supports our WebOb version
     "Beaker==1.6.4",
     "WebHelpers==1.3",
     "formencode>=1.2.4,<=1.2.6",