The concept of PFLAG dates back to 1972, when a young man was attacked at a gay rights protest demonstration in New York. His parents saw the attack on television and witnessed the failure of the police to intervene. The man's mother, Jeanne Manford (1920 – 2013) marched with her son in New York's Pride Day parade that year, and was persuaded to begin a support group, which held its first formal meeting in March 1973.

Following the 1979 National March for Gay and Lesbian Rights, representatives from various support groups for parents with gay and lesbian children met for the first time in Washington, D.C.

In 1981, they launched a national PFLAG  (Parents and Friends of Lesbians and Gays) organization and established the first office in Los Angeles. In 1990, the group consolidated operations in Washington, D.C. and in 1993 added “Families” to their name.

Today PFLAG or similar organizations operate in at least 17 countries around the world.