James McMillan III (born December 1, 1946) is an American political activist and Vietnam War veteran. He was a perennial candidate in New York City.

McMillan is best known as the founder of the Rent Is Too Damn High Party, a New York–based political party. McMillan ran for office at least six times since 1993, most notably in the 2010 New York gubernatorial election. He declared in December 2010 that he would run in the 2012 U.S. presidential election as a Republican. He did not appear on the ballot in any state and suspended his campaign to return to the Rent Is Too Damn High Party and run for Mayor of New York City in the 2013 election. He attempted to run for governor again in the 2014 election but did not make the ballot.

McMillan announced his candidacy for the Republican nomination for President of the United States in the 2016 election, but withdrew from the campaign on December 9, 2015. He subsequently announced that he was retiring from politics before endorsing Republican candidate Donald Trump. The Rent Is Too Damn High Party website announced that McMillan would come out of retirement to make a fourth run for governor. His petitions were challenged and ruled invalid in September 2018.