A letter sent to all parents at Hermitage Academy described the first year pupil as a “cherished member of Arran House”.
It stated: “Her tragic loss will be felt by all staff and pupils.”
The school’s head teacher Douglas Morgan, said: “Olivia was a much-loved member of our school community and an important part of the P7 group at Hermitage Primary, who recently joined us at Hermitage Academy.
“Her loss is felt profoundly by staff, pupils, and families alike.
“We extend our heartfelt sympathies to Olivia’s family and friends during this very difficult time.”
Mr Morgan added that a quiet space has been prepared at the school for any pupil or staff member needing time to reflect or talk about the death.
An online fundraiser, external has been set up by a family friend to give the 11-year-old a “beautiful farewell”.
Organiser Christina Blair wrote: “Olivia was a bright, loving, and unforgettable soul who touched the hearts of everyone who knew her. “
Jackie Baillie, the local MSP for Dumbarton, said her thoughts were with Olivia’s family and friends.
She added: “I am advised by Police Scotland that the investigation into the cause of Olivia’s tragic death is still ongoing and is currently being treated as unexplained.
“It is important that we get answers on what caused her death in order to ensure this unthinkable tragedy cannot be repeated.”
Argyll and Bute Council said it was providing support to Olivia’s family along with staff and pupils at the school.
