It follows the launch of 24-hour services on the Central, Victoria, Jubilee, Piccadilly and Northern lines.
The overground service will start operating from December on Fridays and Saturdays between New Cross Gate and Dalston Junction.
It is also expected to extend to Highbury and Islington next year, Mayor of London Sadiq Khan said.
"Our Night Tube services have been a real success right across the capital, so I'm delighted to announce that we'll be bringing the Night Overground to the East London line later this year", he added.
Due to Crossrail work taking place at Whitechapel station, London Overground night services will initially not call at that station until works are complete.
Services are expected to call at Whitechapel from summer 2018.
The Night Tube is also expected to extend to parts of the Metropolitan, Circle, District, and Hammersmith and City lines once modernisation programmes are complete in 2023.
This year marks the 10th anniversary of the London Overground.
The East London route is to become a Night Tube service, it has been announced.