Diffun is politically subdivided into 33 barangays.
- Andres Bonifacio (Poblacion)
- Aurora East (Poblacion)
- Aurora West (Poblacion)
- Baguio Village
- Balagbag
- Bannawag
- Cajel
- Campamento
- Diego Silang
- Sittio Der-an
- Don Mariano Perez, Sr.
- Doña Imelda
- Dumanisi
- Gabriela Silang
- Gulac
- Guribang
- Ifugao Village
- Isidro Paredes
- Rizal (Poblacion)
- Liwayway
- Luttuad
- Magsaysay
- Makate
- Maria Clara
- Rafael Palma (Don Sergio Osm)
- Ricarte Norte
- Ricarte Sur
- San Antonio
- San Isidro
- San Pascual
- Villa Pascua
- Aklan Village
- Gregorio Pimentel
- Don Faustino Pagaduan