Hugh Mahon (6 January 1857 – 28 August 1931) was an Australian politician. He was a member of the Australian Labor Party (ALP) and held ministerial office in the party's earliest governments. He served terms as Postmaster-General (1904), Minister for Home Affairs (1908–1909), and Minister for External Affairs (1914–1916). However, Mahon is chiefly known as the only person to be expelled from the Parliament of Australia, for making "seditious and disloyal utterances" about the British Empire. He failed to win his seat back at the by-election.