Benalla police are asking for assistance to locate 15-year-old Ava, who was last seen in the Benalla area on Tuesday, November 15.
Ava is described as having fair skin, a thin build, long dark hair with a red rinse, and is about 170cm tall.
Police have concerns for her welfare due to her age and the length of time she has been missing.
Police believe Ava may be in the Benalla, Wodonga, Melbourne CBD or St Kilda areas.
If you have seen Ava or have any information on her whereabouts, phone the Benalla Police Station on 5760 0200.