David Kenneth Harbour (born April 10, 1975) is an American actor. He has received nominations for two Primetime Emmy Awards, a Tony Award, and a Golden Globe Award. 

He began his career acting in Shakespearean theatre productions. After his professional debut on Broadway in the 1999 revival of The Rainmaker, he was nominated for a Tony Award for his performance in a production of Who's Afraid of Virginia Woolf?. He made his television debut on Law & Order in 1999 and had supporting roles in films such as Brokeback Mountain (2005), Revolutionary Road (2008) and Black Mass(2015).

Harbour gained global recognition for his portrayal of Jim Hopper in the Netflix science fiction series Stranger Things (2016–present), for which he received a Critics' Choice Television Award as well as nominations for two Primetime Emmy Awards. His starring film roles include the title character in Hellboy (2019), Santa Claus in Violent Night (2022) and a former racer in the sports film Gran Turismo (2023). In the Marvel Cinematic Universe, Harbour has played Red Guardian since the film Black Widow (2021).