Ronald John McNeill, 1st Baron Cushendun (April 30, 1861) - (October 12, 1934) was a British statesman and politician. Born in Ulster, he was educated at Harrow and Christ Church, Oxford, graduating in 1886. After being called to the bar in 1888, he worked as editor of the St James's Gazette (1900-1904) as well as assistant editor of the Encyclopædia Britannica (1906-1910).

Having unsuccessfully contested the seats of West Aberdeenshire (1906), South Aberdeen (1907 and 1910), and Kirkcudbrightshire (1910), McNeill was elected Unionist Member of Parliament for the St Augustine's division of Kent in 1911. Seven years later he became representative for Canterbury, and in 1922 was appointed Parliamentary Under Secretary of State for Foreign Affairs, a post he held, with a short interval, until 1925.

After serving as Financial Secretary to the Treasury for two years, McNeill was in 1927 made Chancellor of the Duchy of Lancaster with a seat in the Cabinet. He was also that year created Baron Cushendun, of Cushendun in the County of Antrim, taking his title from the village he had designed by Clough Williams Ellis in memory of his Cornish wife, Mary, who died in 1925.

Acting Foreign Secretary in 1928 and twice chief British representative to the League of Nations, it was Lord Cushendun who signed the Kellogg-Briand Pact in August that year. He retired from office in 1929, and died five years later in Cushendun.