diff --git a/io_scene_gltf2/__init__.py b/io_scene_gltf2/__init__.py
index 0b68c8ba11c55277af3fe046679034f3dda538f1..7318487e49dac4701e8146c152a34b48049f57f6 100755
--- a/io_scene_gltf2/__init__.py
+++ b/io_scene_gltf2/__init__.py
@@ -348,7 +348,8 @@ class ExportGLTF2_Base:
         export_settings['gltf_displacement'] = self.export_displacement
 
         export_settings['gltf_binary'] = bytearray()
-        export_settings['gltf_binaryfilename'] = os.path.splitext(os.path.basename(self.filepath))[0] + '.bin'
+        export_settings['gltf_binaryfilename'] = os.path.splitext(os.path.basename(
+            bpy.path.ensure_ext(self.filepath,self.filename_ext)))[0] + '.bin'
 
         return gltf2_blender_export.save(context, export_settings)