Dolga Njiva (pronounced [ˈdoːu̯ɡa ˈnjiːʋa], German: Langenacker[2][3] or Douganiwa[4]) is a former village in eastern Slovenia in the Municipality of Trebnje.

Dolga Njiva lies north of the village center of Gradišče pri Trebnjem.

It stands on a ridge with vineyards above the valley of Pristava Creek (Slovene: Pristavski potok).

[1] Babja Loka Creek flows through the valley immediately south of the settlement.

Dolga Njiva was annexed by Gradišče pri Trebnjem in 1953, ending its existence as a separate settlement.