Described is a garage door panel rail reinforcement device that is configured and constructed to be installed on an upper or lower rail of a “tongue and groove”-type garage door panel. Also, a garage door panel rail reinforcement device that is configured and constructed to be installed on an upper or lower rail of a “ship lap”-style garage door panel is described. Further, an adjustable garage door panel rail reinforcement device is described. In general, some implementations can be configured to fit other profiles of components forming a garage door rail disposed at a meeting point of two adjacent garage door panels.