The position of Secretary of State for War, commonly called War Secretary, a British cabinet-level position, first applied to Henry Dundas (appointed in 1794). In 1801 the post became that of Secretary of State for War and the Colonies. The position was re-instated in 1854 and remained until 1 April 1964, when the cabinet position (along with that of First Lord of the Admiralty and Secretary of State for Air) was replaced by the Secretary of State for Defence - in charge of a new united Ministry of Defence. The former office of the Secretary of State for War became the that of the new Minister of Defence for the Army .

The Secretary of State headed the War Office and was assisted by a Parliamentary Private Secretary, who was also a Member of Parliament, and a Military Secretary, who was a general.

Secretaries of State for War, 1794-1801

• Henry Dundas (July 11, 1794 - March 17, 1801) (also President of the Board of Control)

Secretaries of State for War, 1854-1966

• Henry Pelham-Clinton, 5th Duke of Newcastle (June 12, 1854 - January 30, 1855)
• Fox Maule-Ramsay, 1st Baron Panmure (February 8, 1855 - February 21, 1858)
• Jonathan Peel (February 26, 1858 - June 11, 1859)
• Sidney Herbert (June 18, 1859 - July 22, 1861)
• Sir George Cornewall Lewis (July 23, 1861 - April 13, 1863) (died in office)
• George Robinson, 2nd Earl of Ripon (April 28, 1863 - February 16, 1866)
• Spencer Compton Cavendish, Marquess of Hartington (February 16, 1866 - June 26, 1866)
• Jonathan Peel (July 6, 1866 - March 8, 1867)
• Sir John Pakington (March 8, 1867 - December 1, 1868)
• Edward Cardwell (December 9, 1868 - February 17, 1874)
• Gathorne Hardy (February 21, 1874 - April 2, 1878)
• Sir Frederick Arthur Stanley (April 2, 1878 - April 21, 1880)
• Hugh Culling Eardley Childers (April 28, 1880 - December 16, 1882)
• Spencer Compton Cavendish, Marquess of Hartington (December 16, 1882 - June 9, 1885)
• William Henry Smith (June 24, 1885 - January 21, 1886)
• Gathorne Gathorne-Hardy, 1st Viscount Cranbrook (January 21, 1886 - February 6, 1886)
• Sir Henry Campbell-Bannerman (February 6, 1886 - July 20, 1886)
• William Henry Smith (August 3, 1886 - January 14, 1887)
• Edward Stanhope (January 14, 1887 - August 11, 1892)
• Sir Henry Campbell-Bannerman (August 18, 1892 - June 21, 1895)
• Henry Charles Keith Petty-Fitzmaurice, 5th Marquess of Lansdowne (July 4, 1895 - November 12, 1900)
• William St John Brodrick (November 12, 1900 - October 6, 1903)
• Hugh Oakeley Arnold-Forster (October 6, 1903 - December 4, 1905)
• Richard Burdon Haldane, 1st Viscount Haldane (1911) (December 10, 1905 - June 12, 1912)
• John Edward Seely (June 12, 1912 - March 30, 1914) (resigned)
• Herbert Henry Asquith (March 30, 1914 - August 5, 1914)
• Horatio Herbert Kitchener, 1st Earl Kitchener of Khartoum (August 5, 1914 - July 5, 1916) (died in office)
• David Lloyd George (July 6, 1916 - December 5, 1916) (resigned)
• Edward George Villiers Stanley, 17th Earl of Derby (December 10, 1916 - April 18, 1918)
• Alfred Milner, 1st Viscount Milner (April 18, 1918 - January 10, 1919)
• Winston Churchill (January 10, 1919 - February 13, 1921)
• Sir Laming Worthington-Evans (February 13, 1921 - October 19, 1922)
• Edward George Villiers Stanley, 17th Earl of Derby (October 24, 1922 - January 22, 1924)
• Stephen Walsh (January 22, 1924 - November 3, 1924)
• Sir Laming Worthington-Evans (November 6, 1924 - June 4, 1929)
• Thomas Shaw (June 7, 1929 - August 24, 1931)
• Robert Crewe-Milnes, 1st Marquess of Crewe (August 25, 1931 - November 5, 1931)
• Douglas McGarel Hogg, 1st Viscount Hailsham (November 5, 1931 - June 7, 1935)
• Edward Frederick Lindley Wood, 3rd Viscount Halifax (June 7, 1935 - November 22, 1935)
• Alfred Duff Cooper (November 22, 1935 - May 28, 1937)
• Leslie Hore-Belisha (May 28, 1937 - January 5, 1940) (dismissed)
• Oliver Stanley (January 5, 1940 - May 11, 1940)
• Anthony Eden (May 11, 1940 - December 22, 1940)
• David Margesson (December 22, 1940 - February 22, 1942)
• Sir P.J. Grigg (February 22, 1942 - July 26, 1945)
• Jack Lawson (August 3, 1945 - October 4, 1946)
• Frederick Bellenger (October 4, 1946 - October 7, 1947)
• Emanuel Shinwell (October 7, 1947 - February 28, 1950)
• John Strachey (February 28, 1950 - October 26, 1951)
• Anthony Henry Head (October 31, 1951 - October 18, 1956)
• John Hugh Hare (October 18, 1956 - January 6, 1958)
• Christopher Soames (January 6, 1958 - July 27, 1960)
• John Profumo (July 27, 1960 - June 5, 1963) (resigned)
• Joseph Godber (June 27, 1963 - October 21, 1963)
• James Ramsden (October 21, 1963 - April 1, 1964)