Nicholas Edward McKenna (9 September 1895 – 22 April 1974) was an Australian politician who served as a Senator for Tasmania from 1944 to 1968. He held ministerial office in the Chifley Government from 1946 to 1949 as Minister for Health and Minister for Social Services. He was later Leader of the Opposition in the Senate for a record term of 15 years (1951–1966).