Lee Si-woo (; born September 5, 1997) is a South Korean actress and model under Big Picture Entertainment. She is best known for her roles in ' (2021), Be My Boyfriend (2021), Shooting Stars (2022) and ' (2022).
Lee made her debut as a model under Big Picture Entertainment. She made her acting debut in ' in 2021, playing the role as Bing Bing and Lee Ji-hun. She was cast as the lead in the web series Be My Boyfriend as Oh Ji-na in 2021. She was also cast for the role of Jin Yu-Na in Sh**ting Stars (2021). In 2026, Lee had a supporting role in the fantasy romantic-comedy No Tail to Tell which aired on SBS. She played Geum-ho opposite Kim Hye-yoon and Lomon.