diff --git a/requirements-dev.txt b/requirements-dev.txt
index dfc2d38c6f1edb57721ecfd8cacde943d43d8f07..0d466765f83e466e463327872971485da6f03f74 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -14,3 +14,4 @@ sphinx-autoapi
 setuptools_scm
 yapf>=0.25
 km3net-testdata>=0.2.11
+km3io