Duncan MacMillan

Duncan MacMillan or Duncan Macmillan may refer to:
 * Duncan Macmillan (playwright), a British playwright and director.
 * Duncan Macmillan (art historian), Scottish academic and writer
 * Duncan Macmillan (athlete) (1890–1963), British track and field athlete competitor in the 1912 Summer Olympics
 * Duncan MacMillan (Bloomberg), co-founder of Bloomberg L.P.
 * Duncan Macmillan (Canadian politician) (1837–1903), Canadian lawyer and Member of Parliament
 * Duncan MacMillan (Nova Scotia politician) (1897–1969), former Nova Scotia politician
 * Duncan Bruce MacMillan, former Alberta politician