Police have said "an altercation between a group of youths" occurred near Morres Steet in Bentleigh, which is near Bentleigh train station, just after 8pm yesterday.
Officers arrived to find a 40-year-old Bentleigh East woman with a stab wound to her upper body and two 17-year-old girls, from Bentleigh East and Mentone, with head injuries.
All three were taken to the Alfred hospital in a stable condition.
A 14-year-old Balwyn girl and a 15-year-old Kew girl were then arrested nearby the scene.
They are speaking with police investigating the incident.
Police have said it is believed the teenagers were known to each other.
Anyone who witnessed the incident or with information is urged to contact police.