Nesseby (Unjárga in Sami) is a municipality in the county of Finnmark, Norway.

The municipality is situated on the isthmus between the Varangerfjord and the river of Deatnu (Tana in Norwegian). People live in small settlements along the fjord, the municipal centre being at Nyborg.

Most inhabitants are of Sami origin, and today Sami is being taught as the first language in schools. The municipality has its own Sami dialect and its own Sami costume.

Wild reindeer used to cross the isthmus in prehistoric times up to around 1900, causing extensive human activity througout the millennia. Therefore, the area is full of archeological finds from different periods.