Admiral of the Fleet Sir Osmond de Beauvoir Brock, GCB, KCMG, KCVO (5 January 1869 – 15 October 1947) was a Royal Navy officer. Brock served as assistant director of naval intelligence and then as assistant director of naval mobilisation at the Admiralty in the early years of the 20th century. During the First World War Brock commanded the battlecruiser HMS Princess Royal at the Battle of Heligoland Bight and at the Battle of Dogger Bank. He then commanded the 1st Battlecruiser Squadron with his flag in HMS Princess Royal at the Battle of Jutland.