The Kingspan Stadium has had graffiti written on it.
There was graffiti that supported the victims of the London fire.
Kingspan is the main sponsor of the rugby team.
Kingspan's business practices were criticized by the inquiry into the tower block fire, but the company said its products made up 5% of the insulation at the fire.
The damage was reported to the Police Service of Northern Ireland on Monday.
There was a lot of graffiti over the front of the building.
Criminal damage to Kingspan Stadium overnight has led to contact with the Police Service of Northern Ireland.
The club thanked local residents for their help and support.
There will be no further comment while the investigation is going on.