A coupler for securing an accessory to a motorized vehicle and comprising an accessory attachment component securable to the accessory and a coupler frame securable to the vehicle. The accessory attachment component includes an accessory pivotal connector and an accessory positioning connector. The coupler frame has a coupler pivotal support defined in the coupler frame configured to receive and pivotally support the accessory pivotal connector and a coupler positioning support configured to receive and guide the accessory positioning connector in a coupled configuration. The accessory positioning connector is aligned with the coupler positioning support when the accessory pivotal connector is received in the coupler pivotal support and slidable toward the coupled configuration. The coupler further comprises a locking mechanism engageable with the accessory attachment component and the coupler frame to lock the accessory attachment component and the coupler frame in the coupled configuration.