John Mann (born June 27, 1985) is an American water polo player. He led the University of California team to the 2006 NCAA Championship, and he played for the United States national team at the 2012 Summer Olympics.
Mann played on the water polo team at Corona del Mar High School and won three CIF titles. As a senior, he scored 109 goals and was named the Orange County Player of the Year. He was also named to the All-America first team.
Mann then joined the University of California, Berkeley team. He scored 22 goals as a freshman in 2003. As a sophomore, he led the Bears with 60 goals, was named the team MVP, and was also a first team All-American. The following season, he scored 56 goals to lead the team again. He repeated as team MVP and was named to the All-America first team.
In 2006, Mann scored a team-leading 80 goals and led California to the NCAA Championship. He was a first team All-American for the third straight year and also won the Peter J. Cutino Award as the nation's best male collegiate water polo player. He finished his college career with 218 goals, the second-most in school history.
Mann scored five goals at the 2007 Pan American Games, helping the U.S. win the tournament. He was part of the team in the 2007, 2008, and 2009 FINA World League Super Finals. The 2008 squad finished second. In the 2011 FINA World League Super Finals, he scored six goals, and the U.S. was fourth. At the 2012 Summer Olympics, he scored three goals, and the U.S. finished eighth.
In 2009-2010, Mann played for Club C.N. Barceloneta. He helped the team win the Spanish Cup and the Spanish league championship.
In 2013, Mann signed for Serbian VK Crvena Zvezda, reigning European champions.
Mann was born in Beverly Hills, California, on June 27, 1985. His father played football at Purdue.