The Diocese of Satu Mare (Latin: Dioecesis Satmariensis; Hungarian: Szatmári Római Katolikus Püspökség) is a Latin diocese of the Catholic Church in Romania.

It was established on 23 March 1804 by Francis I, King of Hungary, an act recognised by Pope Pius VII that 9 August.

It was constituted in its present form on 18 October 1982, when the Communist regime split it from the Oradea Mare Diocese.

It covers the counties of Satu Mare and Maramureş, of which 8.2% are Roman Catholic, with concentrations in Satu Mare County along the Hungarian border.

Its adherents are predominantly Hungarians, with a small number of Zipser Germans.