The Grand Fleet was the main fleet of the British Royal Navy during the First World War.

It was formed in August 1914 from the First Fleet and elements of the Second Fleet of the Home Fleets and it included 35-40 state-of-the-art capital ships. It was initially commanded by Admiral Sir John Jellicoe. He was succeeded by Admiral Sir David Beatty in 1916.

The Grand Fleet was based first on Scapa Flow in the Orkney Islands and later at Rosyth on the Firth of Forth and only took part in one fleet action during the war - the indecisive Battle of Jutland.

After the war the Grand Fleet was disbanded with much of its strength forming a new Atlantic Fleet.

Not all the Grand Fleet was available to put to sea at any one time, because ships required maintenance and repairs. For a list of ships which were present at the Battle of Jutland in May 1916 see the article, Order of battle at Jutland. A number of others missed the battle for one reason or another. Actual strength of the fleet varied through the war as new ships were built and others were sunk, but the numbers steadily increased as the war progressed and the margin of superiority over the German fleet progressed with it. This led to a slowly less cautious approach to the war as the strength increased. The fleet was at its weakest at the start of the war, when it was also least experienced at this sort of warfare and a number of minor but embarrassing losses occurred because of this inexperience. After the United States entered the war, United States Battleship Division Nine was attached to the Grand Fleet as the Sixth Battle Squadron, adding four, and later five, dreadnought battleships.