The indie-rock favourites, who are playing a rescheduled show at the Hydro in Glasgow tomorrow, will be headlining the event at Balado three years after they last topped the bill.
The Sheffield band, famed for notching up the fastest-selling debut album in British music history, first played in 2006 at the festival, which celebrates its 20th anniversary next year.
Their headline slot has been confirmed ahead of the next batch of tickets for the three-day event in July going on sale on Friday.
Festival director Geoff Ellis said: “We’re thrilled to announce Arctic Monkeys as our first headliners for T in the Park 2014.
“After this year’s fantastic celebrations, we asked our audience who they’d like to see at next year’s festival and Arctic Monkeys came top of the poll, so we’re really pleased to be able to confirm them.
“When they take to the stage in Glasgow this week they’ll prove exactly why they’re one of the greatest live acts around and I’m sure we can look forward to another phenomenal set. We have many more fantastic acts in store which we’ll announce next year.”
George Kyle, head of sponsorship at Tennent’s, the long-time backers of the festival, said: “This year’s T in the Park was one of the best ever and I’m sure we have another wonderful weekend in store next July.”