diff --git a/main.tf b/main.tf
index 0f642b9..b1f453c 100644
--- a/main.tf
+++ b/main.tf
@@ -73,6 +73,7 @@ resource "aws_ec2_transit_gateway_vpc_attachment" "this" {
   dns_support                                     = try(each.value.dns_support, true) ? "enable" : "disable"
   ipv6_support                                    = try(each.value.ipv6_support, false) ? "enable" : "disable"
   appliance_mode_support                          = try(each.value.appliance_mode_support, false) ? "enable" : "disable"
+  security_group_referencing_support              = try(each.value.security_group_referencing_support, false) ? "enable" : "disable"
   transit_gateway_default_route_table_association = try(each.value.transit_gateway_default_route_table_association, true)
   transit_gateway_default_route_table_propagation = try(each.value.transit_gateway_default_route_table_propagation, true)