BBC Three will stop being broadcast and become an online-only channel in March, the BBC has announced.
The BBC Trust has approved the proposals, designed to save money. They attached the condition that BBC Three's long-form programmes will air on BBC One and Two.
"The decision to close a TV channel is a difficult one, and one we have not taken lightly," said BBC Trustee Suzanna Taverne. "The evidence is very clear that younger audiences are watching more online and less linear TV."
The decision follows a public consultation on the matter.
The BBC must fulfil certain conditions specified by the Trust to ensure that the BBC Three audience is not left wanting. These include offering distinctive new programmes aimed at younger audiences, and to commission risk-taking shows that experiment with new talent and ideas.
TV stars Matt Lucas, Daniel Radcliffe and Olivia Colman have all spoken out against the closure.
However, BBC Three controller Damian Kavanagh insists this is "just the beginning for BBC Three". He set out his plans in a blog.
BBC Three launched in 2003. It succeeded BBC Choice – the first British TV channel to broadcast exclusively in the digital format.