Sagene is a borough of the city of Oslo, Norway. The area became part of the city of Oslo (then Christiania) in 1859.

The name Sagene itself is the plural of the Norwegian word for "saw", reflecting all the old industrial mechanical saws powered by the river Akerselva in this area in the 19th and early 20th centuries.

The borough of Sagene includes the areas of Sagene, Bjølsen, Iladalen, Sandaker, Åsen and Torshov. It is the smallest borough of Oslo, but compared to its relatively small size, it has a noteworthy population by Norwegian standards. In the west its border is the street Uelandsgate and the cemetery (gravlund) Nordre gravlund. In the north it borders Tåsen and Storo. The border then follows the valley Torshovdalen in the east, and borders the areas of Rodeløkka and Grünerløkka is the south.

Running through the borough of Sagene is the river Akerselva which has contributed in shaping the culture and history of the borough. The river has been exploited for energy, and along it for a thousand years, mills and turbines have been operating.