diff --git a/scripts/xy_grid.py b/scripts/xy_grid.py
index 417ed0d4..45a78db2 100644
--- a/scripts/xy_grid.py
+++ b/scripts/xy_grid.py
@@ -393,6 +393,6 @@ class Script(scripts.Script):
             )
 
         if opts.grid_save:
-            images.save_image(processed.images[0], p.outpath_grids, "xy_grid", prompt=p.prompt, seed=processed.seed, grid=True, p=p)
+            images.save_image(processed.images[0], p.outpath_grids, "xy_grid", extension=opts.grid_format, prompt=p.prompt, seed=processed.seed, grid=True, p=p)
 
         return processed