Oslograben or Oslo Graben is a rift valley in southeastern Norway that includes the capital city Oslo. It is surrounded by the Scandinavian Mountains on its west, north and east side, and borders the northernmost point of the Skagerrak to its south. Because of its geography, Oslo is one of the most smog-prone regions in the world.

Geologically, Oslograben is an inactive intracontinental rift. It contains Europe's only known deposit of emeralds.