diff --git a/setup.py b/setup.py
index f3d2ec580f4..db5f911734d 100644
--- a/setup.py
+++ b/setup.py
@@ -70,6 +70,7 @@
     "flake8==3.9.2",
     "isort==5.8.0",
     "m2r2~=0.2.7",
+    "mistune==0.8.4",
     "myst-parser~=0.14.0",
     "rinohtype~=0.4.2",
     "sphinx~=3.5.0",