diff --git a/changelog.d/11056.misc b/changelog.d/11056.misc
new file mode 100644
index 000000000..dd701ed17
--- /dev/null
+++ b/changelog.d/11056.misc
@@ -0,0 +1 @@
+Remove dead code from `MediaFilePaths`.
diff --git a/synapse/rest/media/v1/filepath.py b/synapse/rest/media/v1/filepath.py
index eb66b749a..bec77088e 100644
--- a/synapse/rest/media/v1/filepath.py
+++ b/synapse/rest/media/v1/filepath.py
@@ -48,23 +48,6 @@ class MediaFilePaths:
     def __init__(self, primary_base_path: str):
         self.base_path = primary_base_path
 
-    def default_thumbnail_rel(
-        self,
-        default_top_level: str,
-        default_sub_type: str,
-        width: int,
-        height: int,
-        content_type: str,
-        method: str,
-    ) -> str:
-        top_level_type, sub_type = content_type.split("/")
-        file_name = "%i-%i-%s-%s-%s" % (width, height, top_level_type, sub_type, method)
-        return os.path.join(
-            "default_thumbnails", default_top_level, default_sub_type, file_name
-        )
-
-    default_thumbnail = _wrap_in_base_path(default_thumbnail_rel)
-
     def local_media_filepath_rel(self, media_id: str) -> str:
         return os.path.join("local_content", media_id[0:2], media_id[2:4], media_id[4:])