Youngseo
- Born
- 13 November 2005 (20 years)
- Place of birth
- Seoul, South Korea
- Gender
- Female
Lee Young-seo (이영서; born November 13, 2005) is a South Korean trainee. She is best known for being a former pre-debut member of the girl group ILLIT. She is now in the co-ed group AllDay Project
