Sir Duncan Ross McLarty, KBE, MM (17 March 1891 – 22 December 1962) was an Australian politician and the 17th Premier of Western Australia.

He campaigned in the 1930 state election as a Nationalist candidate with the slogan 'A practical farmer for a farming electorate', winning the lower house seat of Murray-Wellington.

On 14 December 1946, McLarty succeeded the retired Robert Ross McDonald as leader of the newly formed Liberal Party, which had amalgamated with the Nationalists.

The 1947 election saw the Liberal-Country coalition unexpectedly defeat the Labor government of premier Frank Wise who had held the position for only two years.

He was chairman of the Murray District Hospital Board and held a number of pastoral investments, including a controlling interest in Liveringa station, near Derby.