MI5, a law firm, a fire brigade and the Welsh government are among the best LGBT employers in the UK, according to Stonewall.
Solicitors Pinsent Masons is number one in a list of the top 100 companies for 2019, says the LGBT charity.
Several universities, the British Army, Lloyds Bank and homeless charity St Mungo's also feature.
Stonewall says LGBT-inclusive employers play a "crucial role in changing society".
Its executive director Darren Towers says Pinsent Mansons is "leading the way, championing lesbian, gay, bi and trans equality in the workplace".
"They know that helping staff feel that they can bring their full selves to work doesn't just make a huge difference to individual team members - it makes real business sense too."
'You're happier, you stay longer'
Stonewall says the law firm topped the list because of its inclusive policies, attitudes towards transgender staff and visitors, and involvement in campaigns - including marriage equality in Northern Ireland.
"When you are able to bring your whole self to work, you are more productive, you're happier and you stay longer," says 27-year-old lawyer Finlay Fraser, who's LGBT and works at Pinsent Masons.
"A goal for me is to be as authentic as I can be and I definitely feel like I am where I work."
Finlay believes the reason the company is number one is because of its diverse workforce and the support and understanding it has for its staff.
"A person who is LGBT and BAME is going to have a different experience than someone who is white and LGBT," he says.
"This company does a lot of work recognising that those two groups will have different experiences.
"It creates an environment where employees from diverse backgrounds want to work."
'We've got rainbow flags flying'
As well as Pinsent Masons, the other companies which make the top five are Cheshire Fire and Rescue Service, MI5, the National Assembly for Wales and law firm Bryan Cave Leighton Paisner.
Cheshire's fire brigade - which is third - was recognised for its support networks and the work it does with LGBT people in the community.
"There are a lot of factors, particularly among older LGBT people that in theory put them at more risk of fire," says Mark Shone, who works in community safety.
"They're more likely to live alone, perhaps have mental health issues, more likely to be affected by substance misuse and they're all factors that make you at risk of fire.
"We've done a lot of work to trying to map where those people are and engage them in community safety."
A 2018 survey by Stonewall found that more than a third of LGBT staff had hidden they were LGBT at work for fear of discrimination.
Darren Towers adds: "We know that people perform better when they can be themselves. They are more productive, creative and overall, morale is better.
"This is the kind of workforce employers should want and it happens when people are in a workplace where they feel supported and included."