diff --git a/docs/reference/google.auth.compute_engine.rst b/docs/reference/google.auth.compute_engine.rst
index 38785c8..819248c 100644
--- a/docs/reference/google.auth.compute_engine.rst
+++ b/docs/reference/google.auth.compute_engine.rst
@@ -10,5 +10,6 @@
 ----------
 
 .. toctree::
+   :maxdepth: 4
 
    google.auth.compute_engine.credentials
diff --git a/docs/reference/google.auth.crypt.rst b/docs/reference/google.auth.crypt.rst
index be142f4..ff38fa3 100644
--- a/docs/reference/google.auth.crypt.rst
+++ b/docs/reference/google.auth.crypt.rst
@@ -10,6 +10,7 @@
 ----------
 
 .. toctree::
+   :maxdepth: 4
 
    google.auth.crypt.base
    google.auth.crypt.es256
diff --git a/docs/reference/google.auth.rst b/docs/reference/google.auth.rst
index f6ea073..cfcf703 100644
--- a/docs/reference/google.auth.rst
+++ b/docs/reference/google.auth.rst
@@ -10,6 +10,7 @@
 -----------
 
 .. toctree::
+   :maxdepth: 4
 
    google.auth.compute_engine
    google.auth.crypt
@@ -19,6 +20,7 @@
 ----------
 
 .. toctree::
+   :maxdepth: 4
 
    google.auth.app_engine
    google.auth.credentials
diff --git a/docs/reference/google.auth.transport.rst b/docs/reference/google.auth.transport.rst
index 48e2e05..8921863 100644
--- a/docs/reference/google.auth.transport.rst
+++ b/docs/reference/google.auth.transport.rst
@@ -10,7 +10,9 @@
 ----------
 
 .. toctree::
+   :maxdepth: 4
 
    google.auth.transport.grpc
+   google.auth.transport.mtls
    google.auth.transport.requests
    google.auth.transport.urllib3
diff --git a/docs/reference/google.oauth2.rst b/docs/reference/google.oauth2.rst
index 4f1df07..1ac9c73 100644
--- a/docs/reference/google.oauth2.rst
+++ b/docs/reference/google.oauth2.rst
@@ -10,6 +10,7 @@
 ----------
 
 .. toctree::
+   :maxdepth: 4
 
    google.oauth2.credentials
    google.oauth2.id_token
diff --git a/docs/reference/google.rst b/docs/reference/google.rst
index 4b1e085..f122ca1 100644
--- a/docs/reference/google.rst
+++ b/docs/reference/google.rst
@@ -10,6 +10,7 @@
 -----------
 
 .. toctree::
+   :maxdepth: 4
 
    google.auth
    google.oauth2