The Diocese of Leiria–Fátima (Latin: Dioecesis Leiriensis–Fatimensis) is a Latin Church diocese of the Catholic church in Portugal.

It is suffragan diocese in the ecclesiastical province of the Metropolitan Patriarchate of Lisbon.

[1] The main church of the episcopal see is the Cathedral of Our Lady of the Conception, in Leiria.

It also has two minor basilicas, both in Fátima: the Basilica of Our Lady of the Rosary and the Basilica of the Holy Trinity, and also a World Heritage Site: the Monastery of Saint Mary of the Victory, in Batalha, as a decommissioned former Cathedral (now ruined): Church of Our Lady of Pena.

As per 2014, it pastorally served 266,792 Catholics (91.6% of 291,144 total) on 1,700 km2 in 75 parishes and 6 missions with 156 priests (92 diocesan, 64 religious), 767 lay religious (77 brothers, 690 sisters) and 6 seminarians.