A garage door is a large door on a garage that can either be opened manually or by a garage door opener. Although of many designs, most garage doors are sectional, upward-acting, and self-storing. Garage doors are necessarily large to allow passage of automobiles and/or trucks.

Garage doors can be made out of many materials, but steel, aluminum, wood, and vinyl (polyethylene) are the most popular materials.

A common material for a new garage door is roll formed steel sheet to look like a raised panel wooden door. A design mimicking carriage house doors has become quite popular since about 2002, and many manufacturers clad the exterior of a steel door with composite or vinyl boards to give it the appearance of wood. A more economical alternative for garage doors is steel stamped construction.