The band, who last played together in 2012, took fans by surprise when they broke the news on Instagram on Thursday.
They will perform on 20 December, 2019 in Los Angeles at the Shrine Auditorium and Expo Hall. Tickets will be available from 1 November online.
The last time My Chemical Romance played together was in May 2012 at the Bamboozle Festival in Asbury Park, New Jersey.
Almost a year later, frontman Gerard Way announced the band’s split in a long statement.
“My Chemical Romance is done. But it can never die,” he wrote in part.
“It is alive in me, in the guys, and it is alive inside all of you.
“I always knew that, and I think you did too. Because it is not a band – it is an idea.”
My Chemical Romance was formed in 2001. Its first album, I Brought You My Bullets, You Brought Me Your Love. came out in 2002.
Three Cheers for Sweet Revenge followed in 2004, and The Black Parade was released in 2006.
The band’s final album so far, Danger Days: The True Lives of the Fabulous Killjoys, dates back to 2010.