Police are calling for public assistance to help locate missing Templestowe Lower man Justin.
The 21-year-old, who has Autism, was last seen leaving his house in Magnolia Drive about 1.15am on 7 August.
Police and family have concerns for his welfare as his disappearance is out of character.
Justin is Asian, 170cm tall and was last seen wearing a black jacket and black tracksuit pants.
Officers have released an image of Justin and urge anyone with information on his whereabouts to contact Doncaster Police Station on 8841 3999.