diff --git a/setup.py b/setup.py
index a387c605c..7c26a7491 100755
--- a/setup.py
+++ b/setup.py
@@ -192,6 +192,7 @@ def setup_package():
                 'thinc>=6.10.1,<6.11.0',
                 'plac<1.0.0,>=0.9.6',
                 'six',
+                'html5lib==1.0b8',
                 'pathlib',
                 'ujson>=1.35',
                 'dill>=0.2,<0.3',