North and South Yemen are unified to create the Republic of Yemen.

The Yemen Arab Republic, also known as Yemen (Sanaʽa) and was commonly referred to as North Yemen, was a country that existed from 1962 until its unification with the People's Democratic Republic of Yemen in 1990, in the northwestern part of what is now Yemen. Its capital was at Sana'a. It bordered the South Yemen to the southeast, Saudi Arabia to the north and Red Sea to the west, sharing maritime borders with Djibouti and the People's Democratic Republic of Ethiopia.

South Yemen, officially the People's Democratic Republic of Yemen (PDRY), abbreviated to Democratic Yemen, was a country in South Arabia that existed in what is now southeast Yemen from 1967 until its unification with the Yemen Arab Republic in 1990. The sole communist state in the Middle East and the Arab world, it comprised the southern and eastern governorates of the present-day Republic of Yemen, including the islands of Perim, Kamaran, and the Socotra Archipelago. It bordered the Yemen Arab Republic to the northwest, Saudi Arabia to the north, Oman to the east, the Arabian Sea to the southeast, and the Gulf of Aden to the south. Its capital and largest city was Aden.

The Yemeni unification took place on 22 May 1990, when the People's Democratic Republic of Yemen and the Yemen Arab Republic united, forming the Republic of Yemen.

Yemen, officially the Republic of Yemen, is a country in West Asia. Including the Socotra Archipelago, mainland Yemen is located in southern Arabia; bordering Saudi Arabia to the north, Oman to the northeast, the south-eastern part of the Arabian Sea to the east, the Gulf of Aden to the south, and the Red Sea to the west, sharing maritime borders with Djibouti, Eritrea, and Somalia across the Horn of Africa. Covering roughly 455,503 square kilometres, with a coastline of approximately 2,000 kilometres, Yemen is the second largest country on the Arabian Peninsula. Sanaa is its constitutional capital and largest city. Yemen's estimated population is 34.7 million, mostly Arab Muslims. It is a member of the Arab League, the United Nations, the Non-Aligned Movement and the Organisation of Islamic Cooperation.