An undercover Financial Times reporter worked as a hostess at the Presidents Club Charity Dinner and alleges she and other hostesses were sexually harassed.
The hospital said it had no involvement and was shocked by the claims.
The venue, London's upmarket Dorchester Hotel, has launched an investigation.
It was "deeply concerned", it said.
The dinner was for men only, apart from hired hostesses, and was attended by senior figures in business and finance.
A Great Ormond Street Hospital spokeswoman said: "We have had no involvement in the organisation of this event and were never due to receive money from it."
She added: "We would never knowingly accept donations raised in this way.
"All monies raised in our name go to support vital work. However, due to the wholly unacceptable nature of the event we are returning previous donations and will no longer accept gifts from the Presidents Club Charitable Trust."
In a statement, the Presidents Club said: "The organisers are appalled by the allegations of bad behaviour at the event asserted by the Financial Times reporters. Such behaviour is totally unacceptable. The allegations will be investigated fully and promptly and appropriate action taken."
Madison Marriage, the Financial Times reporter who worked at the event, says hostesses were not warned that they might be sexually harassed.
Ms Marriage told BBC Newsnight: "I was groped several times and I know there are numerous other hostesses who said the same thing happened to them.
"It's a hands up skirts, hands on bums but also hands on hips, hands on stomachs, arms going round your waist unexpectedly.
"This isn't, I suppose, a high-level groping, but one of the strangest things was you could be talking to a man and he'd suddenly start holding your hand.
"I knew stuff like that might happen on the night but I wasn't 100% sure. But there are plenty of other women there who had absolutely no idea that was the kind of event it would be and I had one woman tell me that she was shocked. She was asked if she was a prostitute on the night."
Ms Marriage said that the 130 hostesses were told to wear skimpy black outfits with matching underwear and high heels and also that they could drink alcohol while working.
WPP, the world's biggest advertising agency, has said it is withdrawing its future support for the dinner after the allegations.
WPP sponsored a table at the dinner, which took place at London's Dorchester Hotel last Thursday.
Boss Sir Martin Sorrell told the BBC his guests did not see such behaviour and was not at this year's event at London's Dorchester Hotel, but said: "I have never seen anything like that.
"We checked with our people who were there at our table and they said they saw nothing of that kind - but we issued a statement saying that we won't support the charity in future, which is regrettable because it is a charity that supports numerous children's charities and has done a lot of good work."
Maria Miller, chair of the Women and Equalities select committee, told the BBC: "I think that at a time when Hollywood and Westminster are getting their act in order, tackling sexual harassment - to see so many members of the top establishment British business involved in an event like this,
"I think really does give cause for concern and really has to bring into question as to whether or not the laws are strong enough in this area."
Jess Phillips MP, who chairs the Women's Parliamentary Labour Party, told the BBC: "I am tired of having to continually say it's 2018 and it's totally unacceptable that women should be hired in as a herd to entertain a group of entitled rich men, because it's not what we're teaching our kids is an acceptable thing."
Scotland's First Minister Nicola Sturgeon tweeted: "This is brave reporting from the FT, exposing behaviour that is outrageous and unacceptable."
Skip Twitter post by @NicolaSturgeon
Read More (...)