The Roman Catholic Diocese of St. George's in Grenada (Latin: Dioecesis Sancti Georgii) is a diocese, of the Latin Rite of the Roman Catholic Church in the Caribbean, which encompasses only and the entirety of Grenada. It is a suffragan of the Metropolitan Archdiocese of Castries (Saint Lucia) and a member of the Antilles Episcopal Conference, het depends on the missionary Roman Congregation for the Evangelization of Peoples. Cathedral Episcopal See is Immaculate Conception Cathedral, in national capital St. George's, Grenada.

It was erected on 20 February 1956 as Diocese of St. George's in Grenada, on British Antillian territory split off from the Metropolitan Archdiocese of Port of Spain.

As per 2014, it pastorally served 46,485 Catholics (45.4% of 102,295 total) on 340 km² in 20 parishes Episcopal Ordinaries Suffragan Bishops of Saint George’s in Grenada Justin James Field, Dominican Order (O.P.) (born England, UK) (1957.01.14 – death 1969.08.04) Patrick Webster, Benedictine Order (O.S.B.) (born Saint Lucia) (1970.03.07 – 1974.11.18), succeeding as former Titular Bishop of Otočac (1969.06.26 – 1970.03.07), Auxiliary Bishop of Saint George’s in Grenada (1969.06.26 – 1970.03.07) and Apostolic Administrator of Saint George’s in Grenada (1969.08.05 – 1970.03.07); later Metropolitan Archbishop of Castries (Saint Lucia) (1974.11.18 – retired 1979.05.10), died 1989 Sydney Anicetus Charles (born Trinidad and Tobago) (1974.11.18 – retired 2002.07.10 - died 2018.09.04 Vincent (Matthew) Darius, O.P. (born Grenada) (2002.07.10 – death 2016.04.26) Clyde Martin Harvey (born Trinidad and Tobago) (2017.06.23 – ...), no previous prelature.