The musician died at a clinic in Rosenheim, Germany, surrounded by members of his family, according to a statement issued by his publicist.
Manzarek formed the Doors after a chance meeting in July 1965 on Venice Beach, Los Angeles, with Jim Morrison, a fellow alumni from the film school who was to become the band's vocalist.
After they were joined by Robby Krieger on guitar and John Densmore on drums, the band released six albums, all of which were successful. After Morrison's death in 1971, the band continued on as a trio, releasing two more albums.
Manzarek, who was born and raised in Chicago and studied at the Department of Cinematography at UCLA, Manzarek occasionally sang for the Doors and was portrayed by Kyle MacLachlan in the 1991 film biopic about the band.
"I was deeply saddened to hear about the passing of my friend and bandmate Ray Manzarek today," Krieger said in a statement. "I'm just glad to have been able to have played Doors songs with him for the last decade. Ray was a huge part of my life and I will always miss him."
Manzarek played in several other bands after the Doors, including Nite City, a rock group which released a number of albums in the 1970s.
In 1998 he wrote a best-selling memoir about his experiences, Light My Fire: My Life with the Doors. He is survived by his wife Dorothy, a son, and three grandchildren.