Leonard Joseph "Len" Cariou (born September 30, 1939) is a Canadian actor.
Cariou is best known for his role of Sweeney Todd in the original cast of Sweeney Todd: The Demon Barber of Fleet Street, which earned him a Tony Award for Best Actor in a Musical and a Drama Desk Award in 1979. He now plays Henry Reagan, NYPD Police Commissioner (retired), in the multi-generational television series Blue Bloods on CBS.