Lee Yoo-mi (born July 18, 1994) is a South Korean actress. She is known for her roles as Ji-yeong / Player 240 in Squid Game (2021), Lee Na-yeon in All of Us Are Dead (2022), Gang Nam-soon in Strong Girl Nam-soon (2023), and Jo Jae-mi in Mr. Plankton (2024). She won the Primetime Emmy Award for Outstanding Guest Actress in a Drama Series for her role as Ji-yeong in Squid Game, making her the first Korean actress to win in the category.