A gazebo cover adaptable for gazebos having different sized canopies include a fabric panel having a central opening and a perimeter defining at least three adjacent perimeter portions. The fabric panel includes a plurality of centrally-converging gussets extending between the perimeter and the central opening. A closure, for example, a slide zipper, is provided for selectively opening the gussets to form a relatively large canopy sized to fit a predetermined large size canopy frame, and for selectively closing the gussets to form a relatively small canopy sized to fit a predetermined small size canopy frame. A peak cap is positioned over and attached to the central opening of the fabric panel for closing the central opening.