People's Democratic Republic of Yemen (South Yemen) (1967–1990 state)

South Yemen, officially the People's Democratic Republic of Yemen (Arabic: جمهورية اليمن الديمقراطية الشعبية‎ 'Jumhūriyat al-Yaman ad-Dīmuqrāṭīyah ash-Sha'bīyah'), was a country that existed from 1967 to 1990 as a state in the Middle East in the southern and eastern provinces of the present-day Republic of Yemen, including the island of Socotra. It was also referred to as Democratic Yemen or Yemen (Aden).

South Yemen's origins can be traced to 1874 with the creation of the British colony of Aden and the Aden Protectorate, which consisted of two-thirds of the present-day Yemen. However, Aden became a province within the British Raj in 1937. After the collapse of Aden Protectorate, a state of emergency was declared in 1963 when the National Liberation Front (NLF) and the Front for the Liberation of Occupied South Yemen (FLOSY) rebelled against British rule.

The Federation of South Arabia and the Protectorate of South Arabia merged to become South Yemen on 30 November 1967 and became a Marxist socialist republic in 1970 supported by the Soviet Union. It was the only communist state to be established in the Arab world. Despite its efforts to bring stability into the region, it was involved in a brief civil war in 1986. With the collapse of communism, South Yemen was unified with the Yemen Arab Republic (commonly known as "North Yemen") on 22 May 1990, to form the present-day Yemen. After four years, however, South Yemen declared its secession from the north, which resulted in the north occupying south Yemen and the 1994 civil war. Another attempt to restore South Yemen continues on since 2017.