Grandparents Bridget O'Reilly (46), Thomas O'Reilly (45) and their three-year-old grandson Tom O'Reilly lived at Waller's Lot in Cashel.
The three were rear seat passengers in a car which hit a wall in the Windmill Knockbulloge area at around 9pm last night.
"I want to express my sincere condolences and the sympathies of every member of An Garda Síochána to the family and friends of Thomas, Bridget and Tom on this tragic loss of life."
He continued: "A male, age 22 years and a female, age 22 years, both front occupants of the car were removed from the scene to Tipperary University Hospital, Clonmel. Both remain in hospital today, the male is being treated for serious injuries, the female being treated for less serious injuries. All five occupants of the car are members of the same family. A Family Liaison Officer has been appointed to the family to provide support and the family will be kept updated as to the course of the investigation."
The road at Windmill remains closed today and a technical and forensic examination is being carried out by An Garda Síochána Forensic Collision investigators.
An incident room has been established at Cahir Garda Station and an investigation has commenced under a Senior Investigating Officer as An Garda Síochána investigate all the circumstances of the incident.
Superintendent Ruane asked that any person with any information on the collision contact the investigation team at Cahir Garda Station.
"I want to speak with any person who may have been driving on local roads between Golden and Cashel and who may have any camera footage (including dashcam) or images from these roads between 8.15pm and 8.45pm to contact the investigation team at Cahir Garda Station," he said.
