The veteran journalist is set to join radio station LBC in an "opinion-led programme." The station said Marr "will give his view on the biggest issues of the moment, along with agenda-setting guests."
Marr said leaving the BBC to join Global, which owns LBC, would give him "a new freedom" to do journalism with "no filter". He'll also present for Classic FM.
The 62-year-old tweeted: "l leave behind many happy memories and wonderful colleagues."
He added: "I think British politics and public life are going to go through an even more turbulent decade, and as I’ve said, I am keen to get my own voice back.
"I have been doing the Andrew Marr Show every Sunday morning for 16 years now and that is probably more than enough time for anybody!"
Marr joined the BBC in May 2000 as political editor, he'll join LBC (part of the Global network) from the new year.
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