Canopies traditionally come in the form of canopy kits, and once erected, provide portable shelter for property, outdoor parties, etc. However, while canopies are useful in a wide variety of applications, the erected canopy structure is often restricted to a fixed size. The present invention discloses a canopy structure kit for a canopy that is transversely expandable from a first width, typically wide enough for an automobile, to a second width, typically wide enough for two automobiles. The expandable canopy structure kit includes extension members to expand the frame structure, and at least one cover adapted to fit the erected frame structure, whether the frame structure assumes an expanded or unexpanded configuration.