| Jurisdiction: | Diocese |
| Joaçaba | |
| Latin: | Dioecesis Ioassabensis |
| Local: | Diocese de Joaçaba |
| Country: | Brazil |
| Rite: | Latin Rite |
| Cathedral: | Cathedral of St. Therese of the Child Jesus |
| Area Km2: | 10,202 |
| Population: | 310,000 |
| Population As Of: | 2006 |
| Catholics: | 225,000 |
| Catholics Percent: | 72.6 |
| Metro Archbishop: | Wilson Tadeu Jönck, SCI |
| Emeritus Bishops: | Osório Bebber |
| Map: | File:Diocese de Joaçaba.svg |
The Roman Catholic Diocese of Joaçaba (Latin: Dioecesis Ioassabensis) is located in the ecclesiastical province of Florianópolis, in Santa Catarina state, Brazil. The seat of the diocese is the Cathedral of St. Therese of the Child of Jesus, Joaçaba. It is bordered by the Catarinense dioceses of Chapecó, Caçador and Lages, as well as the dioceses of Erexim and Vacaria on the south and the diocese of Palmas–Francisco Beltrão on the north.