Lisa Power, the policy director of Terrence Higgins Trust, has collected her MBE from Buckingham Palace.
She joined the charity in 1996 and was honoured for services to sexual health and to the LGBT community.
Ms Power was given her honour by Prince Charles yesterday after being named in the New Year honours list.
She has 25 years of campaigning for sexual health and LGBT rights, having co-founded gay charity Stonewall and the Pink Paper.
She has also worked at the Lesbian & Gay Switchboard and as secretary general of the International Lesbian and Gay Association.
Gay footballer and co-founder of Stonewall FC, Aslie Pitter, also collected his MBE yesterday.