An attic door support and trimming system includes a plurality of frame sections each having a base wall with an inner edge, an outer edge, a top side and a bottom side, a first end and a second end. A vertical wall extends upwardly from the base wall and is spaced from the inner and outer edges. The first and second ends of different frame sections are positionable against each other to form a rectangular shaped frame. The frame sections each are telescopic to allow a size of the rectangular shaped frame to be adjusted. The top side of the first flange is abuttable against the ceiling adjacent to the opening and the top of the second flange supports a cover when the cover is placed in a closed position closing the opening.