A guide and rail assembly and system for stabilizing a shower door and stationary panel of a shower enclosure are disclosed. The assembly includes an exterior slider bracket configured for mounting on top edge of stationary panel, an exterior slider guide block configured for mounting on top edge of shower door, and an interior slider bracket configured to be housed within a longitudinal channel of the exterior slider guide block such that exterior slider guide block sets atop interior slider bracket and is secured thereto. The assembly further includes a front housing plate configured for attaching to bottom edge of the shower door, a roller bearing component configured to be slidably disposed along top surface of bottom guard rail of shower enclosure, a rear housing plate, and a cover plate configured to be secured to the rear housing plate. Cover plate and rear housing plate are positioned opposite of bottom edge of shower door from front housing plate such that roller bearing component is slidably disposed therebetween front housing plate and rear housing plate in an assembled configuration.