Rebeka Masarova (Slovak: Rebeka Masárová, pronounced [ˈrebeka ˈmasaːrɔʋa]; born 6 August 1999) is a Swiss professional tennis player. She has career-high WTA rankings of No. 62 in singles and No. 125 in doubles, achieved in 2023.
Masarova won the juniors' 2016 French Open.
Masarova's mother is Spanish and her father is Slovak. Born in Basel, hometown of Roger Federer, she was inspired to start playing tennis from watching Federer play in his first Wimbledon final in 2003.
She started representing Spain in January 2018. On 24 December 2024, she announced that she would represent Switzerland again.
In 2016, Masarova reached the juniors semifinals of the Australian Open, where she lost to defending champion Tereza Mihalíková. Later that year, she won the French Open junior title by defeating second seed Amanda Anisimova in the final. Masarova was defeated by British wildcard entrant Gabriella Taylor in the third round of the junior tournament at Wimbledon.
As top seed, she was runner-up in the girls' singles at the 2017 Australian Open, losing to 11th seed Marta Kostyuk in the final.
2016: Semifinal on WTA Tour debut
Aged 16, Masarova made her WTA Tour singles main-draw debut as a wildcard entrant at the Gstaad Ladies Championship defeating former world No. 1, Jelena Janković, in the first round. She then overcame Anett Kontaveit and fifth seed Annika Beck to reach the semifinals, at which point she lost to fellow Swiss player and eventual champion Viktorija Golubic.
2021–2022: Major debut, WTA 125 doubles title
Masarova made her Grand Slam debut at the 2021 US Open as a qualifier. She reached the second round defeating Ana Bogdan 6–7(9), 7–6(2), 7–6(9) in the longest women's match at this major in the Open Era. Masarova lost to fifth seed Elina Svitolina in the second round.
Partnering with Aliona Bolsova, Masarova won the doubles at the Open Internacional de Valencia, defeating Alexandra Panova and Arantxa Rus in the final.
She was runner-up at the 2022 WTA 125 Swedish Open, losing to Jang Su-jeong in the final. Masarova defeated eighth seed Maria Sakkari in the first round at the 2023 US Open, before losing her next match to Anna Karolína Schmiedlová.
2023–2024: Maiden WTA Tour final
Masarova reached her first WTA Tour final at the ASB Classic in Auckland as a qualifier, where she lost to Coco Gauff. This catapulted her into the top 100 for the first time in her career. At the Dubai, she qualified for the main draw but lost to Aliaksandra Sasnovich in the first round.
Masarova received a wildcard for the main-draw of the WTA 1000 Madrid Open where she reached the third round with wins over compatriot Cristina Bucșa and 20th seed Donna Vekić. She lost to ninth seed Maria Sakkari
She reached the final at the 2024 WTA 125 La Bisbal Open, losing to sixth seed María Lourdes Carlé in three sets.
At the 2024 Thailand Open 2, Masarova defeated Anna Bondár and third seed Wang Xinyu to make it into the quarterfinals, at which point her run was ended by Laura Siegemund.
2025–2026: Three WTA 1000 third rounds