Stonewall is a gay rights campaign organisation in the United Kingdom which was named after the Stonewall Inn of Stonewall riots fame. It was formed in 1989 by Labour Party activists who had been lobbying against section 28 of the Local Government Act. High-profile 'faces' such as Sir Ian McKellen and Michael Cashman were among its founders. Stonewall GB is based in London. Stonewall Scotland has offices in Edinburgh and Glasgow and Stonewall Cymru is based in both Cardiff and Bangor in North Wales.

Although Stonewall was set up to be a professional lobbying organisation rather than a membership organisation, it has diversified into areas such as policy development for the rights of lesbian, gay and bisexual people since Labour came into power.