The disturbance, involving a group of inmates at Low Moss prison at Bishopbriggs, East Dunbartonshire, began yesterday afternoon.
Two members of staff were taken to hospital with minor injuries.
It is understood a handful of prisoners barricaded themselves inside cells.
Last night, a spokeswoman for the Scottish Prison Service said: "We can confirm that there's been an incident under way at Low Moss prison.
"Two members of staff were taken to hospital. They were taken to hospital as a precaution and they suffered only minor injuries.
"An investigation will be held by Police Scotland."
No-one else is thought to have been injured in the disturbance.