The 18-year-old is the sixth teen to be charged in relation to the death of Hashim Mohamed, 18, who was allegedly stabbed near St Kilda beach on December 4 and later died in hospital.
The man was arrested at a bus stop in Deer Park about 5pm yesterday following a public appeal and is being prosecuted as a child.
Mohamed's family spoke with 9News last month and described him as a "good kid" who'd just earned his P-plates three days before his death.
"We are coping through it, there is a lot of support by family and friends and close people," his brother Hanad said at the time.
"He was a good kid, just liked to go out with his friends and a social guy, pretty happy, just (a) normal 18-year-old."
The 18-year-old was due to front a children's court today.