Around 20 firefighters were sent to the Wolves ground when the blaze started in the Sir Jack Hayward Suite in the Billy Wright Stand just before 2am on Sunday. It is believed to have been started accidentally by an electrical appliance.
Firefighters were alerted by security staff at the stadium when the alarms started going off and contained the flames to the one suite, which overlooks the pitch.
Nobody was injured and the bar area was empty at the time.
Wolves have now said the damage caused by the blaze is likely to take "some time" to repair and that hospitality ticket holders affected will be contacted ahead of the next home fixture against Norwich in the FA Cup.
Video footage showed smoke tinged gold by the lights pouring out of the football stadium on Waterloo Road for around two hours as an automated PA message asked people to leave the area.
Andy Howard, watch manager at Wolverhampton fire station, said: "There's been a fire in the bar area.
"It was contained to the room of origin but the bar area and part of the workspace was involved in fire. Otherwise it was just smoke damage to the rest of the floor."
The Billy Wright stand includes the Molineux Suite where conferences and events are held next to the reception area by Waterloo Road.
A West Midlands Fire Service spokesman said they were called at 1.56am and the first crew arrived at the scene in five minutes.
Crews from Wolverhampton, Fallings Park, Willenhall and Bilston were all sent to the football ground on Waterloo Road, where the nearby street was cordoned off.
Police officers were also called to the scene but paramedics were not needed.
The blaze was out by 3.40am and firefighters left the scene at 6.45am but returned at 9am to check on the situation.
Wolves played away at Brentford on Saturday, winning the Premier League match 2-1 after a drone halted play in the first half.