| Jurisdiction: | Diocese |
| Caxias do Sul | |
| Latin: | Dioecesis Caxiensis Australis |
| Rite: | Latin Rite |
| Established: | 8 September 1934 (years ago) |
| Cathedral: | Cathedral of St. Teresa of Ávila |
| Area Km2: | 11,034 |
| Population: | 742,481 |
| Population As Of: | 2004 |
| Catholics: | 668,232 |
| Catholics Percent: | 90.0 |
| Metro Archbishop: | Jaime Spengler |
| Bishop: | José Gislon, OFMCap |
| Emeritus Bishops: | Alessandro Carmelo Ruffinoni, CS |
| Map: | File:Diocese de Caxias do Sul.svg |
| Website: | www.diocesedecaxias.org.br |
The Roman Catholic Diocese of Caxias do Sul (Latin: Dioecesis Caxiensis Australis) is a diocese located in the city of Caxias do Sul in the ecclesiastical province of Porto Alegre in Brazil.
On Wednesday, 16 June 2010, Pope Benedict XVI appointed Auxiliary Bishop Alessandro Carmelo Ruffinoni, CS, then the auxiliary bishop to the Archbishop of Porto Alegre, as the Coadjutor Bishop of Caxias do Sul, to succeed Bishop Moretto.