diff --git a/setupext.py b/setupext.py
index 151807a0c385..4ffdfb1ba786 100644
--- a/setupext.py
+++ b/setupext.py
@@ -939,7 +939,8 @@ def get_install_requires(self):
         if sys.version_info[0] >= 3:
             return ['pyparsing>=2.0.0']
         else:
-            return ['pyparsing>=1.5.6']
+            # pyparsing >= 2.0.0 is not compatible with Python 2
+            return ['pyparsing>=1.5.6,<2.0.0']
 
 
 class BackendAgg(OptionalBackendPackage):