diff --git a/pelican/server.py b/pelican/server.py
index 6ebce8760..25c55303b 100644
--- a/pelican/server.py
+++ b/pelican/server.py
@@ -91,7 +91,9 @@ def get_path_that_exists(self, original_path):
     def guess_type(self, path):
         """Guess at the mime type for the specified file.
         """
-        mimetype = server.SimpleHTTPRequestHandler.guess_type(self, path)
+        # strip trailing slash
+        path = path.rstrip().rstrip("/").rstrip(os.sep)
+        mimetype = super().guess_type(path)
 
         # If the default guess is too generic, try the python-magic library
         if mimetype == 'application/octet-stream' and magic_from_file: