Emergency services were called to Bright Street, near Bright Park, shortly before 1am, and found three people injured.
A 16-year-old boy is expected to undergo surgery for a stab wound to his leg, while a 19-year-old man is being treated for a stab wound to his back. Both remain in Westmead Hospital.
An 18-year-old man is in Liverpool Hospital being treated for a head injury after reportedly being hit with a baseball bat.
Police have been told their injuries are not considered life-threatening.
Cumberland Police established a crime scene and conducted a canvass of the area.
Detectives hope to speak with all three once they are deemed well enough. There have been no arrests.
Until then, police are appealing for anyone with information about the incident to call Granville Police Station or Crime Stoppers.
Anyone with information about this incident is urged to contact Crime Stoppers: 1800 333 000 or https://nsw.crimestoppers.com.au. Information is treated in strict confidence.
