| Jurisdiction: | Diocese |
| Sankt Pölten | |
| Latin: | Dioecesis Sancti Hippolyti |
| Local: | Diözese St. Pölten |
| Coat: | Wappen Bistum St. Pölten.png |
| Country: | Austria |
| Metropolitan: | Sankt Pölten |
| Territory: | Lower Austria |
| Province: | Archdiocese of Vienna |
| Area Km2: | 10,450 |
| Population: | 629,000 |
| Population As Of: | 2017 |
| Catholics: | 501,221 |
| Catholics Percent: | 79.7 |
| Denomination: | Roman Catholic |
| Rite: | Roman Rite |
| Established: | January 28, 1785 |
| Cathedral: | Sankt Pölten Cathedral |
| Patron: | Saint Hippolyte |
| Bishop: | Alois Schwarz |
| Metro Archbishop: | Christoph Schönborn |
| Auxiliary Bishops: | Anton Leichtfried |
| Emeritus Bishops: | Klaus Küng |
| Map: | Bistuemer oesterreich st poelten.png |
| Website: | Website of the Diocese |
The Diocese of Sankt Pölten (Latin: Dioecesis Sancti Hippolyti) is a Latin Church diocese located in the city of Sankt Pölten in the ecclesiastical province of Wien in Austria.