| Jurisdiction: | Diocese |
| Simdega | |
| Latin: | Dioecesis Simdegaënsis |
| Local: | सिमडेगा के सूबा |
| Rite: | Latin Rite |
| Cathedral: | Cathedral of St Anne in Simdega |
| Established: | 28 May 1993 |
| Area Km2: | 2,323 |
| Population: | 640,200 |
| Population As Of: | 2022 |
| Catholics: | 215,301 |
| Catholics Percent: | 33.6 |
| Parishes: | 37 |
| Metro Archbishop: | Vincent Aind |
The Roman Catholic Diocese of Simdega (Latin: Simdegaën(sis)) is a diocese located in the city of Simdega in the ecclesiastical province of Ranchi in India.