The advancement flap is the oldest type of tissue transfer described, first postulated by Celsus in ancient Rome, nearly 2,000 years ago. The classic advancement flap is defined as tissue transfer that slides into a surgical defect in one direction. Both the flap and its underlying pedicle move jointly in a single linear vector. The primary tissue movement consists of the advancement of the flap into the defect, led by the flap’s advancing tip. Secondary tissue movement involves skin peripheral to the defect, which is pulled to the center of the primary defect upon closure. By design, the length of the advancement flap is shorter than the distance it travels, which includes the diameter of the defect. Thus, redundancy forms along the total length of the peripheral tissue. The flexibility of dog-ear placement allows for creativity and options in designing incision lines that rest in cosmetically favorable lines. A detailed discussion on flap design and considerations has been provided in this chapter.