Jarl Ottar or Ottar Jarl (?-970's) was an earl of Geatland who kythes in the Heimskringla (the Saga of Olaf Tryggvasson) and in the Jómsvíkinga Saga.

The Jómsvíkinga Saga tells that Jarl Ottar was the motherly greatfather of Palnetoke, the Jomsviking.

In the Heimskringla, Snorri Sturluson tells that Haakon Sigurdsson fought and slew Jarl Ottar bewhile an onslaught on Geatland for Harald Bluetooth.