| Jurisdiction: | Diocese |
| Joinville | |
| Latin: | Dioecesis Ioinvillensis |
| Local: | Diocese de Joinville |
| Country: |  Brazil |
| Sui Iuris Church: | Latin Church |
| Rite: | Roman Rite |
| Established: | 17 January 1927 (years ago) |
| Cathedral: | Cathedral of St Francis Xavier in Joinville |
| Area Km2: | 9,478 |
| Population: | 986,000 |
| Population As Of: | 2006 |
| Catholics: | 641,000 |
| Catholics Percent: | 65.0 |
| Bishop: | Francisco Carlos Bach |
| Metro Archbishop: | Wilson Tadeu Jönck, SCI |
| Map: | File:Diocese de Joinville.svg |
| Website: | www.diocesejoinville.com.br |
The Roman Catholic Diocese of Joinville (Latin: Dioecesis Ioinvillensis) is a suffragan Latin diocese in the ecclesiastical province of the Metropolitan of Florianópolis in Santa Catarina state, southern Brazil.
Its cathedral episcopal ses is Catedral São Francisco Xavier, dedicated to saint Francis Xavier, in the city of Joinville.
As per 2014, it pastorally served 744,219 Catholics (65.0% of 1,144,952 total) on 9,508 km2 in 53 parishes and 5 missions with 118 priests (64 diocesan, 54 religious), 55 deacons, 228 lay religious (104 brothers, 124 sisters) and 26 seminarians.