Iyasu ("Joshua") (4 February 1887 - 25 November 1935) was the ruler of Ethiopia from 1913 to 1916, when he was deposed. He was never crowned emperor, and as a result is either referred to as "Lij Iyasu" or "Iyasu V". His name is sometimes also written as Eyasu.

Iyasu was a grandson of Menelik II of Ethiopia and son of Shewa Regga, a half-sister of Menelik's eldest daughter Zauditu, and was proclaimed heir apparent in 1909.

As ruler, he continued Menelik's program of modernization, including the establishment of the first police force in Addis Ababa, but he was accused of being a Muslim and deposed 27 September 1916 in favor of his aunt Zauditu.

He evaded capture however, and spent five years at large in the countryside before being taken into custody by Gugsa Araya on 11 January 1921. In 1931 he escaped from imprisonment at Fikke, but was recaptured shortly afterwards.

Iyasu was intitially married to Romanework Mangasha, granddaughter of Emperor Johannes IV, and niece of Menelik II's consort Empress Taitu. Following the desolution of that married he married Seble Wongel Hailu, who was the granddaughter of King Tekle Haimanot of Gojjam. He additionally seems to have had at least thirteen secondary wives, and an uncertain number of natural children several of whom have been Iyasuist claimants to the Imperial throne. His only legitmate daughter was Imebet-hoi Alem Tsehai Iyasu, by his legal wife Seble Wongel of Gojjam.