For 1971 Mustang was totally redesigned. Although still based on the original 1965 design, the car now featured a 109 inch wheelbase, but the overall length was now 7.1 inches longer than the original design, and 6.8 inches wider. The grille opening now extended from fender to fender, and the car was lower. The rear window in the coupe models were now recessed as the lines of the rear pillar extended beyond the window. The windshield wipers were concealed beneath the trailing edge of the hood.

The Boss 302 and Boss 429 engines were no longer available.