Major-General Gerald Russell Smallwood CB DSO MC (18 February 1889 – 3 February 1977) was a senior officer in the British Army during World War II.
Smallwood joined the Royal Warwickshire Regiment in 1911 as a Special Reserve second lieutenant on probation, confirmed in April 1912. In December 1912, after passing his examination, he was transferred to be a regular second lieutenant in the 2nd battalion, East Yorkshire Regiment. In September 1914, after the outbreak of World War I, he was promoted to temporary lieutenant and later that year seconded to the Army Signal Service. He was promoted to captain in 1915. He was twice mentioned in dispatches during the war, and he was awarded the Military Cross in the King's 1916 Birthday Honours.
In 1917 and 1919 he twice held the rank of acting Major while commanding a divisional signals company, and in 1920 he was acting Lieutenant-Colonel while still a substantive Captain. In 1922 he left the Signals to attend the Staff College, Camberley, graduating in late 1923, then in 1924 he was appointed to the War Office as Staff Captain. In 1927 he was finally promoted to Major. In 1934, having been promoted to lieutenant colonel, he was appointed to command his old battalion, the 2nd East Yorkshire Regiment.