diff --git a/setup.cfg b/setup.cfg
index 03c37ab..40651db 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -44,6 +44,7 @@ test_suite = tests
 include_package_data = true
 setup_requires = setuptools >=46.4
 install_requires =
+    numpy ~=1.0
     importlib-resources >=1.3 ; python_version < '3.9'
 
 [options.package_data]