Kamil Majchrzak (; born 13 January 1996) is a Polish professional tennis player. Majchrzak along with Martin Redlicki won the 2013 US Open boys' doubles title after defeating Quentin Halys and Frederico Ferreira Silva in the final. Majchrzak has a career high ATP singles ranking of 102 achieved on 15 July 2019 and a career high ATP doubles ranking of 241 achieved on 8 August 2016.
During the 2019 Australian Open Majchrzak advanced through the qualifying to reach the 1st round. He won the first two sets against a top-10 player Kei Nishikori, but then was forced to retire due to an injury.
In March 2019 Majchrzak celebrated his maiden Challenger triumph at the 2019 Open Harmonie mutuelle in St. Brieuc, France. Two months later he advanced to the 2019 Prosperita Open final with wins over Riccardio Bonadio, Zsombor Piros, No. 5 seeded Dennis Novak and Lloyd Harris to lift his second ATP Challenger trophy.