diff --git a/changelogs/fragments/inventory_dir_ext_compare_fix.yaml b/changelogs/fragments/inventory_dir_ext_compare_fix.yaml
new file mode 100644
index 0000000000..7a06919f8c
--- /dev/null
+++ b/changelogs/fragments/inventory_dir_ext_compare_fix.yaml
@@ -0,0 +1,2 @@
+bugfixes:
+- inventory - When using an inventory directory, ensure extension comparison uses text types (https://github.com/ansible/ansible/pull/42475)
diff --git a/lib/ansible/inventory/manager.py b/lib/ansible/inventory/manager.py
index e93884eecd..6d6dfbd6c8 100644
--- a/lib/ansible/inventory/manager.py
+++ b/lib/ansible/inventory/manager.py
@@ -258,7 +258,7 @@ class InventoryManager(object):
 
                 # initialize and figure out if plugin wants to attempt parsing this file
                 try:
-                    plugin_wants = bool(plugin.verify_file(source))
+                    plugin_wants = bool(plugin.verify_file(to_text(source)))
                 except Exception:
                     plugin_wants = False