diff --git a/setup.cfg b/setup.cfg
index 60f300d3..aded9d17 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -56,6 +56,7 @@ install_requires =
     graphql-ws==0.4.4
     jupyter_server>=2.7
     requests
+    psutil
     tornado>=6.1.0  # matches jupyter_server value
     traitlets>=5.2.1  # required for logging_config (5.2.0 had bugs)