Steven Sherriff, 43, insists he was mistaken for the groper, who had allegedly misbehaved with a 23-year-old girl in a bar in February here.
The girl told her boyfriend who punched Steven, knocking him out. Both men were arrested and later withdrew complaints against each other.
But cops charged Steven with being drunk and sexual assault, the Sun reported.
Belfast-born Steven, who has lived in Dubai for seven years, said, "My lawyer says I will get three to 15 years if convicted. But I never touched her." He admitted being drunk but said: "I'd never do a thing like that no matter how drunk I was."
Married businessman Steven is due in court on June 5. The 26-year-old boyfriend faces a charge of being drunk.
Officials in the Gulf state have prosecuted several Britons for indecent behaviour over the past five years.
Last week a British businesswoman was accused of having drunken sex in the back of a Dubai taxi.
Foreigners jailed in Dubai are deported immediately after completing their sentences.