diff --git a/backend/kesaseteli/applications/api/v1/serializers.py b/backend/kesaseteli/applications/api/v1/serializers.py
index 13aac44973..d2a651a0f8 100644
--- a/backend/kesaseteli/applications/api/v1/serializers.py
+++ b/backend/kesaseteli/applications/api/v1/serializers.py
@@ -224,7 +224,10 @@ class EmployerSummerVoucherSerializer(serializers.ModelSerializer):
     )
 
     target_group = serializers.ChoiceField(
-        choices=get_target_group_choices(), required=False
+        choices=get_target_group_choices(),
+        required=False,
+        allow_blank=True,
+        allow_null=True,
     )
 
     class Meta:
@@ -275,7 +278,9 @@ def _validate_non_draft_required_fields(self, data):
                     }
                 )
 
-    def _update_target_group(self, instance: EmployerSummerVoucher, target_group: str):
+    def _update_target_group(
+        self, instance: EmployerSummerVoucher, target_group: Optional[str]
+    ):
         """
         Update the target_group of the youth voucher if it exists.