Javier "Harvey" Guillén (Latin American Spanish:[xaˈβjeɾ ˈxaɾβi ɣiˈʝen]; born May 3, 1990) is an American actor. He is best known for his role as the human familiar Guillermo de la Cruz in the television series What We Do in the Shadows.

Guillén is the son of Mexican immigrants. He adopted the name Harvey when school teachers could not pronounce his first name. Guillén attended Citrus College, completing the three-year Citrus Singers program in 2005. His father, who was the first person who encouraged him to pursue acting, died of lung cancer in 2017.