The Roman Catholic Diocese of Mysore (Latin: Mysurien(sis)) is a suffragan Latin diocese, in the ecclesiastical province of Bangalore in southern India, yet depends on the missionary Dicastery for Evangelization.

Its cathedral episcopal see is St. Philomena's Cathedral in the city of Mysore in Karnataka.

As per 2014, it pastorally served 105,113 Catholics (1.0% of 10,056,000 total) on 21,051 km2 in 77 parishes with 157 priests (114 diocesan, 43 religious), 1,224 lay religious (309 brothers, 915 sisters) and 19 seminarians.

[1] (all Latin Rite; until 1963 European members of a Latin missionary congregation)[1]