Donald McMillan or MacMillan may refer to:
Donald McMillan (Ontario politician) (1835–1914), Senator from Ontario Donald McMillan (Quebec politician) (1807–1876), who represented Vaudreuil in the 1st Canadian Parliament Donald Baxter MacMillan (1874–1970), American explorer Donald MacMillan (rugby union) (born 1930), rugby union player who represented Australia Don MacMillan (1928-2004), Australian Olympic athlete