John Muldoon (11 July 1865 – 21 November 1938) was an Irish barrister and nationalist politician.
He was a Member of Parliament (MP) for most of the period between 1905 and 1918, representing three different constituencies in the House of Commons of the United Kingdom of Great Britain and Ireland.
He was educated at a local school, at Queen's College, Galway and at the King's Inns.
He was returned unopposed as MP for the Irish Parliamentary Party in North Donegal at a by-election in June 1905 but did not stand again at the general election of January 1906, being deselected by the local clergy.
In July 1911 he resigned and stood for the East Cork seat of fellow Nationalist Captain A. J. C. Donelan, who had been unseated following an election petition, having defeated William O'Brien the previous December.