diff --git a/addons/mrp/models/mrp_bom.py b/addons/mrp/models/mrp_bom.py
index e5af5c3aeb3..9df7955a382 100644
--- a/addons/mrp/models/mrp_bom.py
+++ b/addons/mrp/models/mrp_bom.py
@@ -290,6 +290,8 @@ class MrpBomLine(models.Model):
 
     @api.onchange('parent_product_tmpl_id')
     def onchange_parent_product(self):
+        if not self.parent_product_tmpl_id:
+            return {}
         return {'domain': {'attribute_value_ids': [
             ('id', 'in', self.parent_product_tmpl_id._get_valid_product_attribute_values().ids),
             ('attribute_id.create_variant', '!=', 'no_variant')