'Stonewall' has placed the Inland Revenue among the top ten employers for lesbian, gay and bisexual staff.
The lobbying group said its Corporate Equality Index demonstrated that many major employers are "firmly committed to supporting and developing gay staff".
The British Council was the country's top employer for gay people, Stonewall said. The Revenue was placed joint seventh. PricewaterhouseCoopers shared 17th place with Barclays.
The top 100 employers included 12 FTSE 100 companies and 11 government departments.
Employers were ranked according to criteria "ranging from implemention of an effective equalities policy to having openly gay staff on their board of directors".