The 18-year-old was found with "serious" stab wounds in Rushcroft Road, Brixton on 27 December before 18:15 GMT, police said.
He was taken to a south London hospital where he remains in a critical condition.
An 18-year-old man has been charged and will appear in court on Saturday.
A teenager has been charged with attempted murder after an 18-year-old was knocked off his bike and stabbed near a funfair in south London.