diff --git a/src/markitdown/_markitdown.py b/src/markitdown/_markitdown.py
index 48b8910..3c0b6d1 100644
--- a/src/markitdown/_markitdown.py
+++ b/src/markitdown/_markitdown.py
@@ -1701,6 +1701,9 @@ class MarkItDown:
     def _convert(
         self, local_path: str, extensions: List[Union[str, None]], **kwargs
     ) -> DocumentConverterResult:
+        # Deduplicate the list of extensions
+        extensions = list(set(extensions))
+        
         error_trace = ""
         for ext in extensions + [None]:  # Try last with no extension
             for converter in self._page_converters: