Four boys are being held after a 14-year-old was found with serious injuries.
Three 16-year-old boys and a 15-year-old boy, all from Oxford, are being questioned on suspicion of attempted murder.
Police officers were called by the South Central Ambulance Service just after 4pm on Tuesday, to reports of a boy being stabbed in Blackbird Leys.
The victim, who's 14, was taken to hospital, where he is currently in a serious but stable condition.
Police stepped up patrols in the Coltsfoot Square and Samphire Road areas following the stabbing.
Two teenagers were arrested shortly after the incident, with two further arrests made today (15/06)
Superintendent Bruce Riddell, the Local Policing Area Commander for Oxford, said: “We are continuing to investigate the circumstance of this incident and we have now made four arrests.
“We are appealing for witnesses to this incident that happened just before 4pm in Samphire Road, Blackbird Leys.
“I would urge anybody who witnessed the incident to please contact 101, quoting incident reference 1477 (14/6).
“At this time we are not looking for anyone else in connection with this incident and we believe the victim and the offenders were known to each other.
“However this is a concerning incident which involves young people being involved in serious violence.
“It remains a priority for myself and the Force to divert young people away from such violence.
“We continue to work with our local communities and partners, including our Violence Reduction Unit, the local authority and others, to engage with young people in order to stop them from becoming involved in violence such as this.
“As a result of this incident, our neighbourhood policing teams will be patrolling the area and I would urge anyone with any concerns or information to please speak to them.”