Stonewall is one of four organisations to be granted charitable status following new guidelines that recognise the promotion of equality and diversity as charitable aims.
Ben Summerskill, chief executive of the gay and lesbian equality organisation, said the move would have a 'significant impact' on Stonewall's £1.6 million annual income.
"Some trusts and foundations will only deal with charities, so clearly there are financial advantages," he said.
The Charity Commission had already granted charitable status to Pink Parents, Age Equality Association and the North East Centre for Diversity and Racial Equality before last week's announcement.
Lisa Saffron, executive director of Pink Parents, which campaigns against discrimination suffered by lesbian and gay parents, said becoming a charity had saved it from extinction by enabling it to secure £23,000 in grants since January. "We looked at 50 trusts, approached 10 and got help from four," she said.
Age Equality Association is the first anti-age discrimination charity to be registered.