Marta Olehivna Kostyuk is a Ukrainian professional tennis player. She has career-high WTA rankings of world No. 15 in singles, achieved on 4 May 2026 and No. 27 in doubles, reached in May 2023. Kostyuk has won three WTA Tour singles titles, including a WTA 1000 event at the 2026 Madrid Open, and two titles in doubles. Her best performance at the majors is reaching the semifinals of the 2026 French Open. She is currently the No. 2 player from Ukraine.