Kacper Żuk (born 21 January 1999) is a Polish professional tennis player. Żuk has a career high ATP singles ranking of World No. 162 achieved on 13 September 2021. He also has a career-high ATP doubles ranking of World No. 278, achieved on 9 May 2022. Żuk made his ATP debut at the 2020 ATP Cup, where he represented Poland in a singles match, losing to Marin Čilić of team Croatia.