The Diocese of Szombathely (Latin: Dioecesis Sabariensis) is a Latin suffragan diocese in the ecclesiastical province of the Metropolitan Veszprém in Hungary.

Its cathedral episcopal see is Szombathely Cathedral (Hungarian: Sarlósboldogasszony székesegyházi), dedicated to the Visitation of Our Lady, in the city of Szombathely.

As per 2014, it pastorally served 298,100 Catholics (76.9% of 387,500 total) on 4,660 km² in 142 parishes with 135 priests (105 diocesan, 30 religious), 86 lay religious (30 brothers, 56 sisters) and 16 seminarians.