Police are looking for 15-year-old Ruby, from Olinda, who was last seen on Loomai Crescent in Greensborough on 2 June.
Ruby is described as having pale skin, is tall with a slim build with dark brown shoulder length hair and a nose piercing.
Police are concerned for their welfare due to their age and medical conditions.
Ruby is known to frequent the Greensborough and Alphington areas.
Anyone with information is urged to contact Belgrave Police Station on (03) 9754 6677.
