Mariano Kestelboim (born 6 February 1996) is an Argentine tennis player. He has a career high ATP doubles ranking of world No. 99 achieved on 30 March 2026 and a career high singles ranking of No. 387 achieved on 18 September 2017.
Kestelboim won his maiden ATP Challenger title at the 2025 Challenger de Tigre in doubles partnering Gonzalo Villanueva.