The 1991 Motorcraft Quality Parts 500 was the fourth stock car race of the 1991 NASCAR Winston Cup Series and the 32nd iteration of the event.

The race took place over the days of Sunday, March 17 and Monday, March 18, 1991, due to rain delays that left only the first 47 laps of the race being run on Sunday.

Depending on fuel mileage, Hendrick Motorsports driver Ken Schrader would manage to stretch the final 65 laps of the race on one tank of fuel to take his third career NASCAR Winston Cup Series victory and his first victory of the season.

It has annually hosted NASCAR Winston Cup Series stock car races since its inauguration in 1960.

Alan Kulwicki, driving for his own AK Racing team, would win the pole, setting a time of 31.415 and an average speed of 174.413 miles per hour (280.691 km/h) in the first round.