Michael Dennis Groff (born November 16, 1961, in Van Nuys, California) is a former race car driver who competed in CART and the IRL IndyCar Series and was the 1989 Indy Lights champion.
Driving for a family team, he captured wins at the Milwaukee Mile and Road America and finished third in points.
Groff attempted to make his CART Champ Car debut in the 1990 Indianapolis 500 for Euromotorsport but failed to qualify.
In 1991 Groff initially returned to Euromotorsport but switched to A. J. Foyt Enterprises for the final five races of the season.
As Herta risked being bumped from the field, Groff was tasked with qualifying the car if such a situation had happened.
For the 1996-1997 Indy Racing League season Groff joined Byrd/Cunningham and captured 3 straight top-five finishes to start the season including a third at the Las Vegas Motor Speedway and a second at Walt Disney World Speedway (the first with the series new naturally aspirated cars).
After finishes of 7th, 15th, and 15th to start the season, he was replaced at the Texas Motor Speedway race by John Paul Jr.
Groff attempted to qualify for the 1999 Indianapolis 500 for Team Xtreme Racing but failed to make the field.