Maitlis overtakes Evan Davis who stepped down as host in 2018 after being replacing Eddie Mair on BBC Radio 4 current affairs programme PM.
The BBC has also confirmed that Kirsty Wark will take on an enhanced role on the programme with broadcaster Emma Barnett joining the team.
Wark has been one of the main presenters on the show for more than 20 years.
She said: "There is no better place to be right now on British television as we navigate great shifts in politics, international relations and the way we live our lives.
"I love the fact that Newsnight is equipped with a tremendous mix of people who can deliver impact-making journalism with real flair."
Davis hosted the show since 2014. Speaking about stepping down last year, Davis said: “I would have loved to stay longer at Newsnight and will miss the team who’ve been fantastic, but PM is presenter heaven and jobs like this don’t come along very often, and you have to grab them when you can.”
Newsnight has been broadcast on BBC Two since 1980.