Henry Jackson Thomas (born September 9, 1971) is an American actor. He began his career as a child actor and had a lead role in the film E.T. the Extra-Terrestrial (1982), for which he won a Young Artist Award and received Golden Globe Award, BAFTA Award, and Saturn Award nominations. Thomas also had roles in Cloak & Dagger (1984), Fire in the Sky (1993), Legends of the Fall (1994), Suicide Kings (1997), All the Pretty Horses (2000), Gangs of New York (2002), 11:14 (2003), and Dear John (2010). Thomas was nominated for the Golden Globe Award for Best Supporting Actor – Series, Miniseries or Television Film for his role in the television film Indictment: The McMartin Trial (1997).

More recently, Thomas collaborated with filmmaker Mike Flanagan, appearing in the films Ouija: Origin of Evil (2016), Gerald's Game (2017) and Doctor Sleep (2019) as well as the television series The Haunting of Hill House (2018) and its follow-up series The Haunting of Bly Manor (2020), the former of which earned him a Saturn Award. In 2021, he had a main role in Flanagan's horror series Midnight Mass.