Ethiopian Prime Minister Hailemariam Desalegn has submitted a letter of resignation, the state-affiliated Fana Broadcasting Corporate station reported on Thursday.
The resignation of Hailemariam, in power since 2012, comes amid protracted anti-government protests and follows a nationwide state of emergency last year.
His stepping down from power is unprecedented in the vast East African country.
Hailemariam oversaw a smooth handover following the death of former Marxist rebel Meles Zenawi, turning the relatively little-known politician and technocrat to an influential leader.
However, in 2015, months of anti-government demonstrations spread across Ethiopia, leaving hundreds dead and prompting parliament to declare a 10-month state nationwide state of emergency in October 2016.
The emergency quelled the worst of the violence but periodic uprisings still occur.