Dayana Oleksandrívna Yastremska (Ukrainian: Даяна Олександрівна Ястремська; born 15 May 2000) is a Ukrainian tennis player. She has a career-high WTA singles ranking of 32, achieved in May 2019, and a best doubles ranking of 147, first reached on 1 July 2019. She has won three singles titles on the WTA Tour, as well as three singles and three doubles titles on the ITF Women's Circuit.
Her career-high junior ranking was No. 6 and as a 15 year old, she reached the quarterfinals of the junior girls' singles event and the final of the girls' doubles event at the 2016 Australian Open. She followed that up by reaching the final of the girls' singles at Wimbledon, losing to Anastasia Potapova of Russia in straight sets.
After winning her first ITF title in Brazil, Yastremska made her WTA main-draw debut at the İstanbul Cup, where she received a singles wild card. However, she lost a close first-round match against sixth seed Nao Hibino 6–2, 4–6, 3–6.