William Slattery, O.F.M., is an Irish-born Franciscan who served as Bishop of Kokstad from 1993 to 2010, before being appointed Archbishop of Pretoria and Bishop of South Africa, Military.^[1]

William Mathew Slattery was born at Portlaoise on September 6, 1943, he is a native of Killenaule, County Tipperary, Ireland. Following secondary school in Gormanston College, Liam joined the Franciscans in 1962, attending the Killarney Noviciate, and gained a BA degree from University College Galway. He moved to St. Isidore's College in Rome in order to attend lectures at the Antonianum (Pontifical University of St. Anthony). He obtained the S.T.B. (1968), the S.T.L. (1970) and a Diploma in Christian Archaeology at the Antonianum.^[2] He was ordained in Rome in 1970, before going to South Africa in 1971. He served in various dioceses in South Africa and also in Malawi; he has also been Rector of St John Vianney Seminary, where he also lecturered in Church History from 1985 till 1991. While at St. John Vianney he also completed a degree course in anthropology at the University of South Africa(Unisa).^{[citation needed]}

In 1993 he was appointed Bishop of Kokstad. In 2005 he invited the Irish charity Respond! (founded by his fellow Franciscans) to provide services in the diocese, and in 2009 supported their setting up of a housing association, Silvie. In 2010 he was appointed Archbishop of Pretoria. He retired in 2019,^[3] and was succeeded by Archbishop Dabula Mpako.^[4]