Sir Richard Fletcher, 1st Baronet (1768 - 31 August 1813) was an engineer in the British Army.

Fletcher served in the West Indies being wounded in action during the capture of St. Lucia in 1791. During 1799 he took part in the preparation of the defences for the Turks in the Dardanelles. An expedition in 1800 to reconnoitre the Egyptian port of Alexandria lead to his caputure by the French navy, and he was held prisoner until his release following the capture of Alexandria. Returning to England in 1802 he was subsequently sent to fight in the Battle of Copenhagen before participating in the Peninsular War as chief engineer with the rank of lieutenant colonel to General Sir Arthur Wellesley, the 1st Duke of Wellington . He was responsible for building the celebrated Lines of Torres Vedras, and also saw action at Busaco and at the sieges of Ciudad Rodrigo and Badajoz, taking a wound in the groin in the latter engagment. He returned to England to recover and was made a baronet on December 14, 1812 and awarded a pension. He returned in 1813 and directed the sieges of Pamplona and San Sebastián. He was killed in action during the final assault on San Sebastián on August 31, 1813.

Though buried near San Sebastián, a monument to his memory stands at the western side of the north aisle in Westminster Abbey, London. His eldest son died without issue and one of his five daughters - Harriet married the Rev. William Darwin Fox a 2nd cousin of Charles Darwin.