Gay rights charity Stonewall has listed the top 100 LGBT-friendly employers for 2014.
Gentoo - a north-east England-based property management and sustainability company - was rated as the best company in terms of promoting equal opportunities for people with alternative sexualities.
Nottinghamshire Healthcare NHS Trust also ranked well, just behind Gentoo in second place, while the Manchester-based Co-operative Group rounded out the top three.
The other companies or organisations to make the top ten (in order) are: Accenture, EY, the Home Office, IBM, Simmons & Simmons, Tyne and Wear Fire and Rescue Service and Barclays.
All of these firms were credited by Stonewall for taking a proactive approach to human resources and were assessed on their LGBT-friendly policies through a thorough auditing programme.
Public sector organisations performed particularly well throughout the list, with Leicestershire County Council (11th place), Bristol City Council (15th), North Wales Police (19th) and the Cheshire Constabulary (41st) among those rated highly by the charity.
Stonewall has sought to improve the status of LGBT people in the UK's workplaces and while bosses at the organisation state that things are getting better, they promise their work will not stop until equality is reached.
Ben Summerskill, chief executive of Stonewall, said: "Gentoo and every single employer in the top 100 has performed remarkably this year as competition for a place on the list of gay-friendly employers has never been fiercer.
"This commitment from organisations - across 38 different industries - is changing the face of workplaces for the better for all staff - regardless of their sexual orientation."
Peter Walls, Gentoo's chief executive, welcomed the news his company won the award, describing it as "an amazing achievement" that was a credit to the hard work of his staff.
Stonewall is considered controversial by some critics because of its matter-of-fact "some people are gay, get over it" campaign, but charity bosses argue its approach is winning people over and improving equality.
By Francesca Witney