The Afar triple junction is a triple junction located along a divergent plate boundary dividing the Nubian, Somali, and Arabian plates. This area is considered a present-day example of continental rifting leading to seafloor spreading and producing an oceanic basin. Here, the Red Sea Rift meets the Aden Ridge and the East African Rift. The latter extends a total of 6,500 kilometers (4,000 mi) from the Afar Triangle to Mozambique.

The connecting three arms form a triple junction. The northernmost branching arm extends north through the Red Sea and into the Dead Sea, while the eastern arm extends through the Gulf of Aden and connects to the Mid-Indian Ocean ridge further to the east. Both of these rifting arms are below sea level and are similar to a mid-ocean ridge.

The third rifting arm runs south extending around 4,000 kilometres (2,500 mi) through the countries of Kenya, Uganda, the Democratic Republic of Congo, Rwanda, Burundi, Tanzania, Zambia, Malawi and, finally, Mozambique. This southern rifting arm is better known as the East African Rift or the East African Rift System (EARS), when it includes the Afar Triangle.

At small scale, the tectonics of the Afar region is more complex than a textbook triple junction. An independent microplate, the Danakil (or Arrata) microplate, is found between the Afar rift and the Red Sea rift.

A rift is the result of pulling apart or extension of lithosphere, including the crust, caused by mantle upwelling where hotter asthenosphere magma rises up into the colder lithosphere to stretch and thin it.

The triple rift is thought to have begun in the Late Cretaceous epoch to the Paleogene period. At that time the African plate was experiencing far-field stresses caused by portions of the northern boundary of the African plate subducting under the Eurasian plate. Today, the Arabian plate is experiencing a crustal down pull, or slab pull, that has separated from the African plate. At the same time as the subduction in the north, there was mantle upwelling causing the crust to down warp and swell into domes throughout the East African Rift System. The Kenyan dome has been studied extensively.

The plume is thought to have begun under Lake Tana in Ethiopia. Based on the environmental correlations and current topographic locations of the Jurassic Upper Limestone and Cretaceous Upper Sandstone, the net rock uplift of the Ethiopian Plateau would be 2.2 km (1.4 mi) since c. 150 Mya. The thinned Ethiopian lithosphere could have resulted in ponding from mantle plume and subsequent uplift.

Gani et al. (2007) propose that episodic increase of incision of the Ethiopian Plateau suggests episodic growth rates within the plateau, since the incision rates have no correlation to the past climate events. As an effect of Archimedes' principle of isostatic rebound, 2.05 km uplift has occurred within the last 30 million years. Baker et al. (1972) also suggest that the uplift of this area is sporadic and divided by long periods of stability and erosion. Some periods of uplift are recorded at the end of the Cretaceous that resulted in 400 metres (1,300 ft) of uplift and the end of the Neogene with a staggering 1,500 metres (4,900 ft) in magnitude. The Ethiopian dome experienced its largest uplift coinciding with the end of the Neogene uplift associated with the Kenyan dome. It has been argued that the current Ethiopian plateau is a result of the most recent uplift of 500 metres (1,600 ft) estimated to be an Oligocene–early Miocene event. But the most accepted argument of the plateau is the result of the Paleogene flood-basalts. The uplift associated with both domes has resulted in major structural features due to the swelling and warped crustal extension. The two areas of swelling resulted in a large depression between the two domes and subsidence along the coastal regions. The uplift caused by the Ethiopian dome resulted in a massive faulting area of 1,000 metres (3,300 ft) in the Afar region.