diff --git a/src/pydata_sphinx_theme/toctree.py b/src/pydata_sphinx_theme/toctree.py
index cc0ef0c1c..586cacea5 100644
--- a/src/pydata_sphinx_theme/toctree.py
+++ b/src/pydata_sphinx_theme/toctree.py
@@ -71,14 +71,7 @@ def suppress_sidebar_toctree(startdepth: int = 1, **kwargs):
         )
         if ancestorname is None:
             return True  # suppress
-        if kwargs.get("includehidden", False):
-            # if ancestor is found and `includehidden=True` we're guaranteed there's a
-            # TocTree to be shown, so don't suppress
-            return False
-
-        # we've found an ancestor page, but `includehidden=False` so we can't be sure if
-        # there's a TocTree fragment that should be shown on this page; unfortunately we
-        # must resolve the whole TOC subtree to find out
+
         toctree = get_nonroot_toctree(
             app, pagename, ancestorname, toctree_obj, **kwargs
         )
diff --git a/tests/sites/test_primary_sidebar_toc/conf.py b/tests/sites/test_primary_sidebar_toc/conf.py
new file mode 100644
index 000000000..713af624f
--- /dev/null
+++ b/tests/sites/test_primary_sidebar_toc/conf.py
@@ -0,0 +1,18 @@
+"""Test conf file."""
+
+# -- Project information -----------------------------------------------------
+
+project = "PyData Tests"
+copyright = "2020, Pydata community"
+author = "Pydata community"
+
+root_doc = "index"
+
+# -- General configuration ---------------------------------------------------
+
+html_theme = "pydata_sphinx_theme"
+
+html_copy_source = True
+html_sourcelink_suffix = ""
+
+html_theme_options = {"navigation_with_keys": False}
diff --git a/tests/sites/test_primary_sidebar_toc/index.rst b/tests/sites/test_primary_sidebar_toc/index.rst
new file mode 100644
index 000000000..3aaa44df8
--- /dev/null
+++ b/tests/sites/test_primary_sidebar_toc/index.rst
@@ -0,0 +1,7 @@
+test-primary-sidebar-toc
+========================
+
+.. toctree::
+
+   page
+   sec/index
diff --git a/tests/sites/test_primary_sidebar_toc/page.rst b/tests/sites/test_primary_sidebar_toc/page.rst
new file mode 100644
index 000000000..87ad822e9
--- /dev/null
+++ b/tests/sites/test_primary_sidebar_toc/page.rst
@@ -0,0 +1,5 @@
+============
+Page at Root
+============
+
+Some text.
diff --git a/tests/sites/test_primary_sidebar_toc/sec/index.rst b/tests/sites/test_primary_sidebar_toc/sec/index.rst
new file mode 100644
index 000000000..88f6f90c0
--- /dev/null
+++ b/tests/sites/test_primary_sidebar_toc/sec/index.rst
@@ -0,0 +1,10 @@
+===============
+Section at Root
+===============
+
+Some text.
+
+.. toctree::
+   :hidden:
+
+   subpage
diff --git a/tests/sites/test_primary_sidebar_toc/sec/subpage.rst b/tests/sites/test_primary_sidebar_toc/sec/subpage.rst
new file mode 100644
index 000000000..159000e17
--- /dev/null
+++ b/tests/sites/test_primary_sidebar_toc/sec/subpage.rst
@@ -0,0 +1,15 @@
+===============
+Page in Section
+===============
+
+Some text.
+
+Subsection
+==========
+
+Some text.
+
+Subsubsection
+-------------
+
+Some text.
diff --git a/tests/test_build.py b/tests/test_build.py
index d97316ddc..32388bcff 100644
--- a/tests/test_build.py
+++ b/tests/test_build.py
@@ -1142,3 +1142,23 @@ def test_role_main_for_search_highlights(sphinx_build_factory):
     """
     sphinx_build = sphinx_build_factory("base").build()
     assert sphinx_build.html_tree("index.html").select_one('[role="main"]')
+
+
+def test_primary_sidebar_hidden_when_empty(sphinx_build_factory) -> None:
+    """Test that the primary sidebar does not show up if it is empty."""
+    sphinx_build = sphinx_build_factory("test_primary_sidebar_toc").build()
+    sidebar_primary = sphinx_build.html_tree("page.html").select(
+        "div.bd-sidebar-primary"
+    )[0]
+    assert "hide-on-wide" in sidebar_primary.attrs["class"]
+
+
+def test_primary_sidebar_exist_when_hidden_toctree(sphinx_build_factory) -> None:
+    """Test that the primary sidebar shows up if there are hidden toctrees."""
+    sphinx_build = sphinx_build_factory("test_primary_sidebar_toc").build()
+    for page in ("sec/index.html", "sec/subpage.html"):
+        sidebar_primary = sphinx_build.html_tree(page).select("div.bd-sidebar-primary")[
+            0
+        ]
+        assert "hide-on-wide" not in sidebar_primary.attrs["class"]
+        assert "Page in Section" in str(sidebar_primary)