Jaeden Martell (né Lieberher; born January 4, 2003) is an American actor. He began his career as a child actor, with roles in the comedy drama St. Vincent (2014) and science fiction film Midnight Special (2016). His performance in St. Vincent earned him a nomination for the Critics' Choice Movie Award for Best Young Performer. After playing the title character in the drama The Book of Henry (2017), Martell's breakthrough came with his portrayal of Bill Denbrough in the supernatural horror films It (2017) and It Chapter Two (2019). This led to further leading roles in horror films, such as The Lodge (2019) and Mr. Harrigan's Phone (2022).

Martell had a supporting role in Rian Johnson's mystery comedy Knives Out (2019). Venturing into projects with more mature themes, he played a reserved teenager accused of murder in the Apple TV+ miniseries Defending Jacob (2020). He has since starred in the comedy films Metal Lords (2022) and Y2K (2024).