| Jurisdiction: | Diocese |
| Bettiah | |
| Latin: | Dioecesis Bettiahensis |
| Local: | बेतिया के सूबा |
| Country: |  India |
| Rite: | Latin Rite |
| Cathedral: | Cathedral of the Nativity of the Blessed Virgin Mary in Bettiah |
| Area Km2: | 16,089 |
| Population: | 15,891,000 |
| Population As Of: | 2012 |
| Catholics: | 5,810 |
| Catholics Percent: | 0.0 |
| Parishes: | 12 |
| Bishop: | Fr. Peter Sebastian Goveas |
| Metro Archbishop: | William D'Souza |
The Roman Catholic Diocese of Bettiah (Latin: Bettiahen(sis)) is a diocese located in the city of Bettiah in the ecclesiastical province of Patna in India.
Some of the communicants within this diocese are Bettiah Christians, one of the oldest ethnoreligious Christian communities in the northern Indian subcontinent.[1] Newaris of the Catholic Christian faith who settled in Chuhari in the 1700s after being expelled from Nepal, are part of the Roman Catholic Diocese of Bettiah as well; they are known as Newar Christians.[1] Other Catholic Christian communities who are served by the Roman Catholic Diocese of Betetiah include those of scheduled castes and tribal people.[1]