Otmoor or Ot Moor is an area of wetland and wet grassland in Oxfordshire, England, located halfway between Oxford and Bicester. It is about 60 metres (200 ft) above sea level, and has an area of nearly 400 hectares (990 acres).
It is encircled by the "Seven Towns" of Otmoor: Beckley, Noke, Oddington, Charlton-on-Otmoor, Fencott, Murcott and Horton-cum-Studley.
Part of it is a nature reserve, RSPB Otmoor, which adjoins a Ministry of Defence firing range, which is part of a Site of Special Scientific Interest.