Joe Armstrong is an English actor, best known for his roles in the television series Robin Hood, Happy Valley, and The Village. He has also starred in films such as Darkest Hour and The Hollow Crown.

Armstrong was born in Hammersmith, London, England, in 1978. He is the son of actor Alun Armstrong. He has an older brother, Tom, and a younger brother, Dan, who was in the band Clock Opera. He attended Elliott School in Putney from 1993 to 1997. He then studied at the University of Bristol, where he acted in The Brecht Project—a collection of scenes from the works of Bertolt Brecht—in 1998 and Women Beware Women in 1999.