diff --git a/sphinx/ext/intersphinx/_load.py b/sphinx/ext/intersphinx/_load.py
index ab6a373fea0..d849ff2d8f3 100644
--- a/sphinx/ext/intersphinx/_load.py
+++ b/sphinx/ext/intersphinx/_load.py
@@ -234,7 +234,7 @@ def _display_failures(failures: Sequence[tuple[str, ...]]) -> str:
         try:
             formatted.append(failure_args[0] % failure_args[1:])
         except TypeError:
-            formatted.append(' - '.join(failure_args))
+            formatted.append(' - '.join(map(str, failure_args)))
     return '\n'.join(formatted)
 
 
diff --git a/tests/test_ext_intersphinx/test_ext_intersphinx.py b/tests/test_ext_intersphinx/test_ext_intersphinx.py
index 5fcfe4d9260..e063e3ebbe5 100644
--- a/tests/test_ext_intersphinx/test_ext_intersphinx.py
+++ b/tests/test_ext_intersphinx/test_ext_intersphinx.py
@@ -935,6 +935,7 @@ def test_display_failures():
             'http://example.com',
             'http://proxyhost.net',
         ),  # No '%'
+        (22, 'Invalid argument'),  # Non-string argument
     ]
     issues = _display_failures(failures_args)
     assert 'Failed to fetch inventory from http://example.com' in issues
@@ -943,3 +944,4 @@ def test_display_failures():
         'intersphinx inventory has moved: - http://example.com - http://proxyhost.net'
         in issues
     )
+    assert '22 - Invalid argument' in issues