Satu Mare County (Romanian: Județul Satu Mare, pronounced [ˌsatu ˈmare], Hungarian: Szatmár megye) is a county (județ) of Romania, on the border with Hungary and Ukraine. The capital city is Satu Mare.

In Hungarian, it is known as Szatmár megye, in German as Kreis Sathmar, in Ukrainian as Сату-Маре, and in Slovak as Satmárska župa.

Satu Mare County has a total area of 4,418 square kilometres (1,706 sq mi).

In the north are the Oaș Mountains, part of the Eastern Carpathians. This makes up around 17% of the area. The remainder is hills, forming 20% of the area, and plains. The western part of the county takes up the Eastern part of the Pannonian Plain.

The county is crossed by the Someș River, the Tur River, and Crasna River.

The county lies partly in the historical region of Maramureș and partly in the historical region of Crișana.

Satu Mare County, together with the Bihor, Bistrița-Năsăud, Cluj, Maramureș, and Sălaj counties, constitute the Nord-Vest development region of Romania. The county is a member of the Carpathian Euroregion.

According to the 2021 census, the county had a population of 330,668 and the population density was 74.8/km² (193.8/sq mi).