Morris "Mo" Nunn (born 27 September 1938) is a motor racing team owner and engineer from England. He ran the Ensign Formula One team in the late 1970s and early 80s, and later worked for Chip Ganassi's highly successful Champ Car team, before founding Mo Nunn Racing for the 2000 season.
Running his own team did not prove so successful. Like Ensign, the team was often relatively under-funded. Tony Kanaan, their sole driver in their debut season, never managed a top 5 finish. A second car was added for Alex Zanardi in 2001, but he was uncompetitive and then lost his legs in a horrific crash at Lausitzring. Kanaan finished in 9th in the championship.
In 2002 Nunn entered one car each in Champ Car and the rival Indy Racing League. The IRL entry for Felipe Giaffone proved more competitive than Kanaan's Champ Car entry, encouraging the team to concentrate purely on IRL a year later. With Toyota and Pioneer backing, the former F1 driver Tora Takagi joined the team. He finished 10th in 2003, while Giaffone missed races because of injuries. He was replaced by Alex Barron, who won the Michigan race. For 2004 only one car was entered, for Takagi, whose performance was not impressive after a heavy crash at Twin Ring Motegi. Other than the 2005 Indianapolis 500, Nunn has not since entered a car of his own, instead returning to act as a technical adviser to Chip Ganassi Racing.