Four teenage boys have been stabbed at a fast food outlet in Melbourne's north-west.

Police said a large number of youths turned up for what they described as an "organised brawl" in St Albans just before 6:15pm.

Four boys, all aged 17 years old, sustained stab wounds during the scuffle.

A Braybrook boy and North Melbourne boy sustained serious injuries, while two boys from St Albans and Caroline Springs sustained minor injuries, police said.

The four teenagers were taken to hospital.

Police said they had spoken to a number of witnesses at the scene and were investigating the incident.