| Jurisdiction: | Diocese |
| Muzaffarpur | |
| Latin: | Dioecesis Muzaffarpurensis |
| Country: | India |
| Denomination: | Catholic Church |
| Sui Iuris Church: | Latin Church |
| Rite: | Roman Rite |
| Cathedral: | Cathedral of St Francis Assisi in Muzaffarpur |
| Established: | 6 March 1980 |
| Map: | Roman_Catholic_Diocese_of_Muzaffarpur_in_India.jpg |
| Area Km2: | 27,120 |
| Population: | 29,436,742 |
| Population As Of: | 2004 |
| Catholics: | 4,638 |
| Catholics Percent: | 0.0 |
| Bishop: | Cajetan Francis Osta |
| Metro Archbishop: | William D'Souza |
The Diocese of Muzaffarpur (la| Muzaffarpuren(sis)) is a diocese located in the city of Muzaffarpur in the ecclesiastical province of Patna in India.