The Sahel (; Arabic: ساحل sāḥil [ˈsaːħil], "coast, shore") is a region in Africa. It is defined as the ecoclimatic and biogeographic realm of transition between the Sahara to the north and the Sudanian savanna to the south. Having a hot semi-arid climate, it stretches across the south-central latitudes of Northern Africa between the Atlantic Ocean and the Red Sea.

The Sahel part of Africa includes – from west to east – parts of northern Senegal, southern Mauritania, central Mali, northern Burkina Faso, the extreme south of Algeria, Niger, the extreme north of Nigeria, Cameroon and Central African Republic, central Chad, central and southern Sudan, the extreme north of South Sudan, Eritrea and Ethiopia.

Historically, the western part of the Sahel was sometimes known as the Sudan region (bilād as-sūdān بلاد السودان "lands of the Sudan"). This belt was located between the Sahara and the coastal areas of West Africa.

There are frequent shortages of food and water due to the dry harsh climate. This is exacerbated by the population increasing rapidly due to very high birthrates across the region; Niger has the world's highest fertility rate.

Jihadist insurgent groups including Boko Haram, Islamic State and al-Qaeda frequently carry out major attacks.