diff --git a/sphinx/environment/adapters/toctree.py b/sphinx/environment/adapters/toctree.py
index a765e8fe9..93555d172 100644
--- a/sphinx/environment/adapters/toctree.py
+++ b/sphinx/environment/adapters/toctree.py
@@ -320,7 +320,7 @@ class TocTree:
         toctrees = []  # type: List[Element]
         if 'includehidden' not in kwargs:
             kwargs['includehidden'] = True
-        if 'maxdepth' not in kwargs:
+        if 'maxdepth' not in kwargs or not kwargs['maxdepth']:
             kwargs['maxdepth'] = 0
         else:
             kwargs['maxdepth'] = int(kwargs['maxdepth'])