diff --git a/requirements.txt b/requirements.txt
index 787d78fc..12173505 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,5 +4,6 @@ scipy
 argparse
 scikit-image
 pytest
+numpydoc
 # From python 3.11 and newer, toml is part of standard implementation
 tomli