This is a list of Royal Navy flag officers who died during the First World War. This list includes all officers who are listed by the Commonwealth War Graves Commission (CWGC) as having died while serving during the First World War. During this period flag officers of the Royal Navy were those who held the ranks of rear-admiral, vice-admiral, admiral, or admiral of the fleet. They typically commanded groups of sea-going vessels or held staff positions.
The list includes 10 flag officers who died between Britain's entry into the war, 4 August 1914, and the armistice of 11 November 1918. Listed separately are 6 who died between the armistice and 31 August 1921 which was defined by an act of British parliament as the formal end of the war. Three flag officers were killed in action; one at the 1914 Battle of Coronel and two at the 1916 Battle of Jutland.