The Bab-el-Mandeb (Arabic: باب المندب, lit. 'Gate of Lamentation', Tigrinya: ባብ ኣል ማንዳብ), the Gate of Grief or the Gate of Tears, is a strait between Yemen on the Arabian Peninsula and Djibouti and Eritrea in the Horn of Africa. It connects the Red Sea to the Gulf of Aden and by extension the Indian Ocean.

The strait derives its name from the dangers attending its navigation or, according to an Arab legend, from the numbers who were drowned by an earthquake that separated the Arabian Peninsula from the Horn of Africa.

In "Bab-el-Mandeb", "Bab" means "gate" while "Mandeb" means "lamentation" or "grief".

The distance across is about 26 kilometres (14 nmi) from Ras Menheli in Yemen to Ras Siyyan in Djibouti. The island of Perim divides the strait into two channels, of which the eastern, known as the Bab Iskender (Alexander's Strait), is 5.37 kilometres (2.90 nmi) wide and has a depth of 29 metres; 96 feet (16 fathoms) deep, while the western, or Dact-el-Mayun, has a width of 20.3 kilometres (11.0 nmi) and a depth of 310 metres; 1,020 feet (170 fathoms). Near the coast of Djibouti lies a group of smaller islands known as the "Seven Brothers". There is a surface current inwards in the eastern channel, but a strong undercurrent outwards in the western channel.

The Bab-el-Mandeb acts as a strategic link between the Indian Ocean and the Mediterranean Sea via the Red Sea and the Suez Canal. Most exports of petroleum and natural gas from the Persian Gulf that transit the Suez Canal or the SUMED Pipeline pass through both the Bab el-Mandeb and the Strait of Hormuz. While the narrow width of the strait requires vessels to travel through the territorial sea of adjacent states, under the purview of Article 37 of the United Nations Convention on the Law of the Sea, the legal concept of transit passage applies to Bab el-Mandeb, although Eritrea (unlike the rest of coastal countries) is not a party to the convention.

Chokepoints are narrow channels along widely used global sea routes that are critical to global energy security. The Bab el-Mandeb Strait is 26 kilometres (14 nautical miles) wide at its narrowest point, limiting tanker traffic to two 2-mile-wide channels for inbound and outbound shipments.

Closure of the Bab el-Mandeb Strait could keep tankers originating in the Persian Gulf from transiting the Suez Canal or reaching the SUMED Pipeline, forcing them to divert around the southern tip of Africa, which would increase transit time and shipping costs.

In 2006, an estimated 3.3 million barrels (520,000 m) of oil passed through the strait per day, out of a world total of about 43 million barrels per day (6,800,000 m/d) moved by tankers. This rose by 2014 to 5.1 million barrels per day (b/d) of crude oil, condensate and refined petroleum products headed toward Europe, the United States, and Asia, then an estimated 6.2 b/d by 2018. Total petroleum flows through the Bab el-Mandeb Strait accounted for about 9% of total seaborne-traded petroleum (crude oil and refined petroleum products) in 2017. About 3.6 million b/d moved north toward Europe; another 2.6 million b/d flowed in the opposite direction mainly to Asian markets such as Singapore, China, and India.

Paleo-environmental and tectonic events in the Miocene epoch created the Danakil Isthmus, a land bridge forming a broad connection between Yemen and Ethiopia. During the last 100,000 years, eustatic sea level fluctuations have led to alternate opening and closing of the straits. According to the recent single origin hypothesis, the straits of Bab-el-Mandeb were probably witness to the earliest migrations of modern humans. It is presumed that the oceans were then much lower and the straits were much shallower or dry, which allowed a series of emigrations along the southern coast of Asia.

According to Ethiopian Orthodox Tewahedo Church tradition, the straits of Bab-el-Mandeb were witness to the earliest migrations of Semitic Ge'ez speakers into Africa, occurring c. 1900 BC, roughly around the same time as the Hebrew patriarch Jacob. The Kingdom of Aksum was a major regional power in the Horn of Africa. It extended its rule across the strait with the conquest of the Himyarite Kingdom shortly before the rise of Islam.

The British East India Company unilaterally seized the island of Perim in 1799 on behalf of its Indian empire. The government of Britain asserted its ownership in 1857 and erected a lighthouse there in 1861, using it to command the Red Sea and the trade routes through the Suez Canal. It was used as a coaling station to refuel steamships until 1935 when the reduced use of coal as fuel rendered the operation unprofitable.

The British presence continued until 1967 when the island became part of the People's Republic of South Yemen. Before the handover, the British government had put forward before the United Nations a proposal for the island to be internationalized as a way to ensure the continued security of passage and navigation in the Bab-el-Mandeb, but this was refused.

In 2008 a company owned by Tarek bin Laden unveiled plans to build a bridge named Bridge of the Horns across the strait, linking Yemen with Djibouti. Middle East Development LLC issued a notice to construct a bridge passing across the Red Sea that would be the longest suspended passing in the world. The project was assigned to engineering company COWI in collaboration with architect studio Dissing+Weitling, both from Denmark but the announced delay to Phase 1 in 2010 and the lack of any further updates since makes this a defunct project.

The Bab-el-Mandeb is also a sub-region in the Arab League, which includes Djibouti, Yemen, and Eritrea.

Bab-el-Mandeb:
Country	Area (km)	Population (2016 est.)	Population density (per km)	Capital	GDP (PPP) $M USD	GDP per capita (PPP) $ USD
Yemen	527,829	27,392,779	51.9	Sana'a	$58,202	$2,249
Eritrea	117,600	6,380,803	54.3	Asmara	$9.121	$1,314
Djibouti	23,200	846,687	36.5	Djibouti City	$3.327	$3,351
Total	668,629	34,620,269	51.8 / km	Various	$70,650	$1,841

The most significant towns and cities along both the Djiboutian and Yemeni sides of the Bab-el-Mandeb:

• Khôr ʽAngar
• Moulhoule
• Fagal

• At Turbah
• Cheikh Saïd
• Perim

Strait:

• Red Sea Dam

Region:

• Horn of Africa
• Mashriq

Rail (tunnel or bridge) transport:

• Rail transport in Djibouti
• Rail transport in Eritrea
• Rail transport in Somalia
• Rail transport in Yemen

• "Bab-el-Mandeb" , Encyclopædia Britannica, vol. 3 (11th ed.), 1911, p. 91
• Notice-to-Proceed Launches Ambitious Red Sea Crossing
• Sea crossing