diff --git a/setup.py b/setup.py
index 7b9ecb5a0..2b618d3b0 100644
--- a/setup.py
+++ b/setup.py
@@ -93,7 +93,7 @@
           'jinja2>=3.0',
           'jsonschema>=3.0',
           'matplotlib>=3.1',
-          'numpy>=1.17',
+          'numpy>=1.17,<2',
           'psutil>=5.6',
           'pyerfa>=1.7',
           'python-dateutil>=2.5.3',