Greta Jiehan Lee (born March 7, 1983) is an American actress. She had supporting roles in the Netflix comedy-drama series Russian Doll (2019–2022) and the Apple TV+ drama series The Morning Show (2021–present). The latter earned her a nomination for a Primetime Emmy Award. She gained prominence for her starring role in the romantic drama film Past Lives (2023), for which she received a nomination for a Golden Globe Award for Best Actress.

Lee began her career in theatre, making her Broadway debut in the musical comedy The 25th Annual Putnam County Spelling Bee (2007). She starred in the 2010 revival of the comedic play La Bête on Broadway and the West End. In 2011, she acted in the Amy Herzog play 4000 Miles at Lincoln Center Theatre.