The collision occurred on the A3400 Stratford Road around 5.30pm last night, Wednesday January 26.
A man from one of the vehicles was left with serious injuries and taken to John Radcliffe Hospital for treatment. Five other people from the collision received treatment for minor injuries, which included an elderly man and two 10-year-old children from one vehicle and a teenager and an adult from another vehicle.
A South Central Ambulance Service spokesperson said: "We sent two ambulances and a paramedic team leader in a rapid response vehicle to the incident.
"Our staff worked with the air ambulance team to treat the most serious injured patient before he was taken by road to the major trauma unit at the John Radcliffe Hospital. The air ambulance team accompanied the patient in the back of the ambulance."
All other patents from the collision were treated at the scene by ambulance crews.
Four crews of firefighters responded to the multi-vehicle collision. Crews from Hook Norton, Deddington and Banbury fire stations attended the scene alongside colleagues from Warwickshire Fire & Rescue Service.
A spokesperson for Oxfordshire Fire & Rescue Service said: "Crews worked hard to extract one man from one of three cars that had been involved. Five other people were also assessed and treated by the ambulance service."
Thames Valley Police also attended the collision, but they are not releasing any information on the collision.
The A3400 road was closed for several hours last night, Wednesday January 26, while emergency services attended the collision.