Senator Johnston may refer to:
Members of the Australian Senate Bertie Johnston (1880–1942), Australian Senator from Western Australia from 1929 to 1942 David Johnston (Australian politician) (born 1956), Australian Senator from Western Australia from 2002 to 2016
Members of the Canadian Senate John Frederick Johnston (1876–1948), Canadian Senator from Saskatchewan from 1943 to 1948
Members of the Northern Irish Senate James Johnston (Northern Ireland politician) (1849–1924), Northern Irish Senator from 1921 to 1924 John Stewart Johnston (born 1906), Northern Irish Senator from 1958 to 1965 and from 1967 to 1973 William Ernest George Johnston (1884–1951), Northern Irish Senator from 1949 to 1951
Members of the United States Senate J. Bennett Johnston (1932–2025), U.S. Senator from Louisiana from 1972 to 1997 John W. Johnston (1818–1889), U.S. Senator from Virginia from 1870 to 1883 Joseph F. Johnston (1843–1913), U.S. Senator from Alabama from 1907 to 1913 Josiah S. Johnston (1784–1833), U.S. Senator from Louisiana from 1824 to 1833 Olin D. Johnston (1896–1965), U.S. Senator from South Carolina from 1945 to 1965 Rienzi Melville Johnston (1849–1926), U.S. Senator from Texas in 1913; also served in the Texas State Senate Samuel Johnston (1733–1816), U.S. Senator from North Carolina from 1789 to 1793
United States state senate members Alva Johnston (politician) (1872–1953), Nebraska State Senate David Emmons Johnston (1845–1917), West Virginia State Senate George Doherty Johnston (1832–1910), Alabama State Senate Harry Johnston (American politician) (1931–2021), Florida State Senate Henry S. Johnston (1867–1965), Oklahoma State Senate J. Mark Johnston (born 1962), South Dakota State Senate James Johnston (colonel) (1740s–1805), North Carolina State Senate Joseph F. Johnston (1843–1913), Alabama State Senate Mike Johnston (Colorado politician) (born 1974), Colorado State Senate Mike Johnston (Kansas politician) (born 1945), Kansas State Senate Patrick Johnston (American politician) (born 1946), California State Senate Rod Johnston (1937–2018), Wisconsin State Senate Thomas D. Johnston (1840–1902), North Carolina State Senate W. Broughton Johnston (1905–1978), West Virginia State Senate William Agnew Johnston (1848–1937), Kansas State Senate William Johnston (California politician) (1829–1905), California State Senate
See also Archibald Johnstone (1924–2014), Canadian Senator from Prince Edward Island from 1998 to 1999 Senator Johnson (disambiguation)