The Diocese of Uruguaiana (Latin: Dioecesis Uruguaianensis) is a Latin Church ecclesiastical territory or diocese of the Catholic Church in Rio Grande do Sul state, Brazil.

It is a suffragan diocese in the ecclesiastical province of the metropolitan Archdiocese of Santa Maria.

Its cathedra episcopal see is Catedral Senhora Sant’Ana, dedicated to St. Anne, in Uruguaiana.

As per 2014, it pastorally served 365,000 Catholics (74.5% of 490,000 total) on 35,439 km2 (13,683 sq mi) in 16 parishes and 286 missions with 26 priests (23 diocesan, 3 religious), 63 lay religious (9 brothers, 54 sisters) and 10 seminarians.

This article on a Roman Catholic diocese in Brazil is a stub.