The 65-year-old was placed on the sex offenders register after being found guilty of the assault in December last year.
The former depute provost resigned from the Tories but refused to stand down.
The Standards Commission announced today that the suspension would begin immediately and initially last for three months.
The decision was taken by a panel that determined it was is in the public interest to suspend Cllr Donnelly due to the serious nature of the complaint against him.
Noting that the crux of the complaints was that Councillor Donnelly had failed to comply with the
Councillors’ Code of Conduct, Standards Commission Convener Professor Kevin Dunion said, “The Code of Conduct is clear about the standards of behaviour expected of councillors at all times.
“While the allegations against Councillor Donnelly have not yet been fully investigated by the ESC and are, as such, unsubstantiated, they are of a particularly serious nature.
“We decided that it was in the public interest to impose an interim suspension, to maintain public confidence in the ethical standards framework in Scotland.”
During the trial, Donnelly denied kissing and touching a man who was working at an event he attended. But he was found guilty and ordered to pay compensation.