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.^[1]

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.

Result	W/L	Year	Tournament	Surface	Opponent	Score
Loss	0–1	1975	Sydney Outdoor, Australia	Grass	Ross Case	2–6, 1–6
Loss	0–2	1978	Australian Open, Melbourne	Grass	Guillermo Vilas	4–6, 4–6, 6–3, 3–6

Result	W/L	Year	Tournament	Surface	Partner	Opponents	Score
Win	1–0	1975	Sydney Outdoor, Australia	Grass	Mark Edmondson	Chris Kachel Peter McNamara	6–1, 6–1
Loss	1–1	1976	Palma, Spain	Clay	Mark Edmondson	John Andrews Colin Dibley	6–2, 3–6, 2–6
Loss	1–2	1976	Sydney Outdoor, Australia	Grass	Mark Edmondson	Syd Ball Kim Warwick	3–6, 4–6
Win	2–2	1977	Cairo, Egypt	Clay	John Bartlett	Pat DuPré Chris Lewis	7–5, 6–1, 6–3
Win	3–2	1977	Båstad, Sweden	Clay	Mark Edmondson	Jean-Louis Haillet François Jauffret	6–4, 6–0
Win	4–2	1977	Manila, Philippines	Hard	Chris Kachel	Mike Cahill Terry Moor	4–6, 6–0, 7–6
Loss	4–3	1978	Florence, Italy	Clay	Mark Edmondson	Corrado Barazzutti Adriano Panatta	3–6, 7–6, 3–6
Loss	4–4	1978	Sydney Indoor, Australia	Hard (i)	Mark Edmondson	John Newcombe Tony Roche	4–6, 3–6
Win	5–4	1978	Hong Kong	Hard	Mark Edmondson	Hank Pfister Brad Rowe	5–7, 7–6, 6–1
Loss	5–5	1978	Taipei, Taiwan	Carpet (i)	Mark Edmondson	Sherwood Stewart Butch Walts	2–6, 7–6, 6–7
Loss	5–6	1979	Hamburg, Germany	Clay	Mark Edmondson	Jan Kodeš Tomáš Šmíd	3–6, 1–6, 6–7
Win	6–6	1979	Gstaad, Switzerland	Clay	Mark Edmondson	Ion Țiriac Guillermo Vilas	2–6, 6–1, 6–4
Loss	6–7	1979	Båstad, Sweden	Clay	Mark Edmondson	Heinz Günthardt Bob Hewitt	2–6, 2–6
Win	7–7	1979	Taipei, Taiwan	Carpet (i)	Mark Edmondson	Pat DuPré Robert Lutz	6–1, 3–6, 6–4

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

• John Marks at the Association of Tennis Professionals
• John Marks at the International Tennis Federation