The Roman Catholic Diocese of Trois-Rivières (Latin: Dioecesis Trifluvianensis in Canada) (erected 8 June 1852) is a suffragan of the Archdiocese of Québec.

The Diocese of Trois-Rivières was erected from the Archdiocese of Quebec on June 8, 1852.

At that time, the diocese extended to the Eastern Townships, and included thirty-nine parishes.

[1] The Collège des Trois-Rivières was founded in 1860; in 1874, it became the diocesan seminary.

Notre-Dame-du-Cap was designated a national pilgrimage site by the bishops of Canada in 1909.