The Diocese of Mangalore is a Latin Church ecclesiastical jurisdiction or diocese of the Catholic Church located in the city of Mangalore, India. The diocese is a suffragan in the ecclesiastical province of the metropolitan Archdiocese of Bangalore. At present, it comprises the whole civil districts of Dakshina Kannada and Udupi in Karnataka state. The area of the Diocese was collectively referred to as South Canara during the Company rule in India, in the subsequent British India after Direct rule from London commenced & in the early post-independence Bombay state, prior to the States Reorganisation Act (1956). It was established as a separate Apostolic Vicariate from the Apostolic Vicariate of Verapoly in 1853, and was promoted to a diocese on 1 September 1886.

The Roman Catholic Metropolitan Archdiocese of Bangalore is an ecclesiastical territory or diocese of the Catholic Church in India. It was erected as pro-vicariate from, as Vicariate from, as Diocese of Mysore - Bangalore in the Ecclesiastical Metropolitan Province of Pondicherry in Southern India from, as Diocese of Bangalore on 13 February 1940 by Pope Pius XII, and elevated to the rank of a Metropolitan Archdiocese on 19 September 1953, with the Suffragan Dioceses of Belgaum, Bellary, Chikmagalur, Gulbarga, Karwar, Mangalore, Udupi, Mysore, and Shimoga.