diff --git a/gguf-py/gguf/gguf_writer.py b/gguf-py/gguf/gguf_writer.py
index 3c9213777f..73a8944091 100644
--- a/gguf-py/gguf/gguf_writer.py
+++ b/gguf-py/gguf/gguf_writer.py
@@ -1125,9 +1125,6 @@ class GGUFWriter:
     def add_vision_spatial_merge_size(self, value: int) -> None:
         self.add_uint32(Keys.ClipVision.SPATIAL_MERGE_SIZE, value)
 
-    def add_vision_window_size(self, value: int) -> None:
-        self.add_uint32(Keys.ClipVision.WINDOW_SIZE, value)
-
     def add_vision_use_gelu(self, value: bool) -> None:
         self.add_bool(Keys.ClipVision.USE_GELU, value)