HMS Orion was the lead ship of her class of four dreadnought battleships built for the Royal Navy in the early 1910s. She spent the bulk of her career assigned to the Home and Grand Fleets, generally serving as a flagship. Aside from participating in the failed attempt to intercept the German ships that had bombarded Scarborough, Hartlepool and Whitby in late 1914, the Battle of Jutland in May 1916 and the inconclusive Action of 19 August, her service during World War I generally consisted of routine patrols and training in the North Sea.

After the Grand Fleet was dissolved in early 1919, Orion was transferred to back to the Home Fleet for a few months before she was assigned to the Reserve Fleet. She served as a gunnery training ship from mid-1921 until she was listed for disposal the following year. The ship was sold for scrap in late 1922 and subsequently broken up.