The Apostolic Vicariate of Galla (Latin: Vicariatus Apostolicus Africae inter Populos Galla) was a Roman Catholic mission territory set up in 1846, and embracing the territory of the Oromo people in Abyssinia.
The vicariate dates from 4 May 1846. The Capuchin Guglielmo Massaia,was the first vicar Apostolic. He was consecrated Bishop of Cassia, 24 May 1846, and sent on a mission to the Oromo tribes. Only after five years was he able to reach the region of Galla Assandabo, 20 November 1852. Having evangelized the districts of Goudrou, Lagamara, Limmou, Nonna, and Guera, he entered, 4 October 1859, the Kingdom of Kaffa, where conversions were abundant. He provided the converted tribes with priests, so that when persecution obliged him to flee, Christianity did not disappear.
In 1868 he was at Choa, where he worked until 1879, and enjoyed the confidence of Menelik II of Ethiopia, who made him his confidential counsellor. In the interval the missions of Kaffa and Guera were administered by his coadjutor Bishop Felicissimo Coccino, who died 26 February 1878. In 1879 Negus John of Abyssinia compelled his vassal Menelik to order Bishop Massaia to return to Europe. The bishop had already been banished seven times, and handed over the government of the vicariate to his coadjutor Bishop Taurin Cahagne, from 14 February 1875 titular Bishop of Adramittium.
The mission of Harar was founded by Bishop Taurin, who from 1880 to 1899 worked in this largely Muslim area. He wrote a catechism and works of Christian instruction in the Galla language. The vicariate included the three main districts of Choa, Kaffa and Harar.
For history from 1914 see Roman Catholic Diocese of Djibouti.