Abstract: A retractable mud flap assembly for being able to retract the mud flaps when the box of the dump truck is raised. The retractable mud flap assembly includes a housing having front, top, side, and bottom walls, and also having an open back end, and a hole being disposed through the front wall with the housing being adapted to be attached to either a vehicle or a trailer above rear tires thereof; and also includes bracket members being attached to the housing for fastening the housing to either the vehicle or trailer; and further includes a mud flap support member being movably disposed in the housing; and also includes a mud flap member being attached to the mud flap support member and being movably disposed in and from the housing; and further includes an assembly for moving the mud flap support member and the mud flap member.