This disclosure details accessory rail systems for securing various accessory devices to vehicles that are equipped with either standard roofs or roofs with one or more roof openings. An exemplary accessory rail system includes an accessory rail that is configured to simultaneously mount one or more interior accessories and/or one or more exterior accessories relative to the vehicle. A trim piece may be secured to the accessory rail, and an airbag curtain may be secured to either the accessory rail, the trim piece, or a roof frame rail.