The 12th congressional district of Missouri was a congressional district for the United States House of Representatives in Missouri from 1873 to 1953.

Member	Party	Years	Cong ress	Electoral history
District created March 4, 1873
John M. Glover (La Grange)	Democratic	March 4, 1873 – March 3, 1879	43rd 44th 45th	Elected in 1872. Re-elected in 1874. Re-elected in 1876. Lost renomination.
William H. Hatch (Hannibal)	Democratic	March 4, 1879 – March 3, 1883	46th 47th	Elected in 1878. Re-elected in 1880. Redistricted to the 1st district.
Charles H. Morgan (Lamar)	Democratic	March 4, 1883 – March 3, 1885	48th	Elected in 1882. Lost re-election.
William J. Stone (Nevada)	Democratic	March 4, 1885 – March 3, 1891	49th 50th 51st	Elected in 1884. Re-elected in 1886. Re-elected in 1888. Retired.
David A. De Armond (Butler)	Democratic	March 4, 1891 – March 3, 1893	52nd	Elected in 1890. Redistricted to the 6th district.
Seth W. Cobb (St. Louis)	Democratic	March 4, 1893 – March 3, 1897	53rd 54th	Redistricted from the 9th district and re-elected in 1892. Re-elected in 1894. Retired.
Charles E. Pearce (St. Louis)	Republican	March 4, 1897 – March 3, 1901	55th 56th	Elected in 1896. Re-elected in 1898. Retired.
James Joseph Butler (St. Louis)	Democratic	March 4, 1901 – June 28, 1902	57th	Elected in 1900. Seat declared Vacant.
Vacant		June 28, 1902 – November 4, 1902
James Joseph Butler (St. Louis)	Democratic	November 4, 1902 – February 26, 1903		Elected to fill the vacant seat. Lost election contest.
George C. R. Wagoner (St. Louis)	Republican	February 26, 1903 – March 3, 1903		Won election contest. Retired.
James Joseph Butler (St. Louis)	Democratic	March 4, 1903 – March 3, 1905	58th	Elected in 1902. Retired.
Ernest E. Wood (St. Louis)	Democratic	March 4, 1905 – June 23, 1906	59th	Elected in 1904. Lost election contest.
Harry M. Coudrey (St. Louis)	Republican	June 23, 1906 – March 3, 1911	59th 60th 61st	Won election contest. Re-elected in 1906. Re-elected in 1908. Retired.
Leonidas C. Dyer (St. Louis)	Republican	March 4, 1911 – June 19, 1914	62nd 63rd	Elected in 1910. Re-elected in 1912. Lost election contest.
Michael J. Gill (St. Louis)	Democratic	June 19, 1914 – March 3, 1915	63rd	Won election contest. Lost re-election.
Leonidas C. Dyer (St. Louis)	Republican	March 4, 1915 – March 3, 1933	64th 65th 66th 67th 68th 69th 70th 71st 72nd	Elected in 1914. Re-elected in 1916. Re-elected in 1918. Re-elected in 1920. Re-elected in 1922. Re-elected in 1924. Re-elected in 1926. Re-elected in 1928. Re-elected in 1930. Redistricted to the at-large district and lost re-election.
District inactive		March 4, 1933 – January 3, 1935	73rd	All representatives elected at-large.
James R. Claiborne (St. Louis)	Democratic	January 3, 1935 – January 3, 1937	74th	Redistricted from the at-large district and re-elected in 1934. Lost renomination.
Charles A. Anderson (St. Louis)	Democratic	January 3, 1937 – January 3, 1941	75th 76th	Elected in 1936. Re-elected in 1938. Lost re-election.
Walter C. Ploeser (Chesterfield)	Republican	January 3, 1941 – January 3, 1949	77th 78th 79th 80th	Elected in 1940. Re-elected in 1942. Re-elected in 1944. Re-elected in 1946. Lost re-election.
Raymond W. Karst (St. Louis)	Democratic	January 3, 1949 – January 3, 1951	81st	Elected in 1948. Lost re-election.
Thomas B. Curtis (Webster Groves)	Republican	January 3, 1951 – January 3, 1953	82nd	Elected in 1950. Redistricted to the 2nd district.
District eliminated January 3, 1953

• Election Statistics 1920–present Clerk of the House of Representatives
• Martis, Kenneth C. (1989). The Historical Atlas of Political Parties in the United States Congress. New York: Macmillan Publishing Company.
• Martis, Kenneth C. (1982). The Historical Atlas of United States Congressional Districts. New York: Macmillan Publishing Company.
• Congressional Biographical Directory of the United States 1774–present