Michael Callen (April 11, 1955 – December 27, 1993) was an American singer, songwriter, composer, author, and AIDS activist. He was a significant architect of the response to the AIDS crisis in the United States.
First diagnosed with "Gay related immune deficiency" (GRID) in 1982, Callen quickly became a leader in the response to the epidemic. He was a founding member of the People With AIDS Self-Empowerment Movement among other organizations, and he testified before the President's Commission on AIDS and both houses of the United States Congress.
Callen died of AIDS-related complications in Los Angeles, California, at the age of 38.