John M. P. Marks (born 9 December 1952) is a former professional tennis player from Australia. Marks won the ILTF Western Australian Championships on grass in 1978 at Perth defeating Mark Edmondson, Chris Kachel, and Bob Carmichael in a marathon five set final. Marks would finish as runner-up in the same event in 1979 losing the final to Edmondson. Marks is best remembered for finishing runner-up in singles at the 1978 Australian Open, defeating Arthur Ashe in the semifinals. As a result of this slam final appearance, he achieved his career-high singles ranking of world No. 44, after entering the tournament ranked No. 177. Marks never won a Grand Slam singles title during his career, but won 7 doubles titles and reached the semifinals of the men's doubles at the 1978 US Open. As a junior, Marks won the Australian Open boys' doubles in 1971, partnering Michael Phillips.

Career finals

Singles (2 runners-up )

Doubles (7 titles, 7 runner-ups)

Grand Slam tournament performance timeline

Singles

Note: The Australian Open was held twice in 1977, in January and December.