Andrew Thomas Griffith John (born 9 January 1964) is the Bishop of Bangor in the Church in Wales.
A native of Aberystwyth, John attended Ysgol Penglais before studying law at the University of Wales, Cardiff. After graduating in 1986, he studied theology at the University of Nottingham, graduating in 1988, followed by a Diploma in Pastoral Studies at St John's College, Nottingham in 1989. He was ordained deacon in the Diocese of St David's and a priest in 1990. Until his election as Bishop of Bangor, all his ministry was in the Diocese of St David's. Initially he was curate for Cardigan, Y Ferwig and Mwnt from 1989 to 1991 and then in Aberystwyth from 1991 to 1992. He was a vicar in the Rectorial Benefice of Aberystwyth from 1992 to 1999. From 1999 he was vicar of Henfynyw with Aberaeron and Llanddewi Aberarth, to which was added Llanbadarn Trefeglwys in 2005. In 2006 he was appointed vicar of Pencarreg and Llanycrwys and the Archdeacon of Cardigan.
John was elected Bishop of Bangor on 9 October 2008 and was consecrated in Llandaff Cathedral on 29 November 2008, along with the new Bishop of St David's, Wyn Evans. He was enthroned in Bangor Cathedral on 24 January 2009. John and his wife of 25 years, Caroline, herself a Deacon of the church, announced their separation in December 2016.