The People's Democratic Republic of Ethiopia (PDRE; Amharic: የኢትዮጵያ ሕዝባዊ ዲሞክራሲያዊ ሪፐብሊክ, romanized: Ye-Ītyōṗṗyā Həzbāwī Dīmōkrāsīyāwī Rīpeblīk) was a socialist state that existed in Ethiopia and present-day Eritrea from 1987 to 1991.
The PDRE was established in February 1987 as a Marxist-Leninist one-party state upon the adoption of the 1987 Constitution, three weeks after its approval in the national referendum. The Derg, the military junta that had ruled Ethiopia as a provisional government since 1974, planned for transition to civilian rule and proclaimed a socialist republic in 1984 after five years of preparation. The Workers' Party of Ethiopia (WPE) was founded that same year as a vanguard party led by Derg chairman Mengistu Haile Mariam. The Derg was dissolved with the proclamation of the PDRE, but continued to rule de facto until September when the new government took office, three months after the June general election. It was dominated by surviving Derg members, with Mengistu as both President of Ethiopia and General Secretary of the WPE.