Yoon Seo-A (Korean: 윤서아; born September 30, 2000), born Im Sun-woo (임선우), is a South Korean actress. She made her television debut in 2018 with the drama Bad Papa and gained recognition for her role as Seo Ji-wan in the 2021 Netflix series Nevertheless.

Yoon has since appeared in a variety of television productions, including Love Revolution (2020), True Beauty (2020), Juvenile Justice (2022), Soundtrack #1 (2022), Bloody Heart (2022), and Today’s Webtoon (2022). In 2024, she portrayed Chae Young-ji in Goodbye Earth and Baek Yi in The Tale of Lady Ok.

In 2025, Yoon took on her first leading role as Seo Gil-geum in the fantasy romance series Bon Appétit, Your Majesty, earning praise for her emotional depth and captivating screen presence. Known for her versatility and expressive performances, she continues to establish herself as one of South Korea’s promising young talents.