The 17-year-old was rushed to hospital with stab wounds following the attack around 12.30am on Saturday, May 22.
The incident happened as the teenager was walking with three friends on Milngavie Road near to American Golf in Bearsden.
Four or five male youths wearing balaclavas got out a small dark-coloured car and started chasing them onto Manse Road and Hillside Avenue. One of the suspects had a knife and seriously assaulted the 17 year-old.
Emergency services rushed to the scene and the injured boy was taken to the Queen Elizabeth University Hospital where he was treated then later released.
Police are now appealing for anyone who may have witnessed the attack or with information about the incident to come forward.
Detective Constable Steven Gault said: “Our enquiries are continuing to establish the exact circumstances surrounding this incident. We have been speaking to people in the local area and checking CCTV footage to gather more information for our investigation.
“Anyone who was in the area at the time, who witnessed anything suspicious, or anyone with dash-cam or private CCTV footage is asked to contact us, as they may hold information that will assist our enquiry.
“Any details can be passed to officers at Kirkintilloch Police Station through 101 quoting reference number 0153 of 22 May. Alternatively Crimestoppers can be contacted on 0800 555 111, where anonymity can be maintained.”