Charles Edward de la Barca Macmillan (December 1872 – 9 January 1941) was a New Zealand politician. He was Mayor of Tauranga (1915–1917) and a member of the House of Representatives (1923–1935).

Macmillan was born in Saint Croix in the Danish West Indies in December 1872.^[1] His father, Donald Macmillan,^[2] had been a paymaster with the Royal Navy and was later a sugar planter.^[1] His mother, Maria Elise Barca, was the Baroness de la Barca, the daughter of Baron de la Barca.^[3] Following an uprising by workers in 1879, the Macmillans left Saint Croix.^[3]

Macmillan came to New Zealand with his parents and two siblings on the May Queen in 1881.^[2] They were part of the George Vesey Stewart Special Settlement to Te Puke, however his father wanted to be closer to the sea and thus bought land at Katikati.^[2]

In 1900, he married Ethel Latham. They moved to Tauranga in 1908.^[3]

Macmillan was the 15th Mayor of Tauranga and served from 1915 to 1917. In the 1915 mayoral election, he defeated John Cuthbert Adams.^[4] In the 1917 mayoral election, Adams narrowly defeated Macmillan (by 292 to 276 votes).^[5]

Standing for the Reform Party, he won the Tauranga electorate in the 1923 by-election^[6] after the death of William Herries,^[7] and held it to 1935^[6] when he was defeated by the Labour candidate, Charles Burnett. He was a cabinet minister in the United–Reform Coalition government (Minister of Agriculture and Minister of Mines from 13 February 1932 to 6 December 1935).^[8] He was subsequently granted the right to retain the title of "Honourable", having served more than three years as a member of the Executive Council.^[9] In 1935, he was awarded the King George V Silver Jubilee Medal.^[10]

Macmillan died in Tauranga on 9 January 1941.^[1] He was survived by his wife, his son, two daughters, and two sisters.^[3]