HMS Sir John Moore was a First World War Royal Navy Lord Clive-class monitor named for Sir John Moore, a British general of the Peninsula War who was killed in action during the Battle of Corunna. Her 12" main battery was stripped from the obsolete Majestic-class battleship HMS Hannibal, which had been converted into a troopship.
The Lord Clive class monitors were built in 1915 to engage German shore artillery and positions in occupied Belgium during the First World War. Sir John Moore, with her sisters was regularly engaged in this service in the Dover Monitor Squadron, bombarding German positions along the coast and someway inland with their heavy guns.
Following the armistice in November 1918, Sir John Moore and all her sisters were put into reserve pending scrapping, as the reason for their existence had ended with the liberation of Belgium. In 1921 Sir John Moore and four of her sisters were scrapped.