Duncan Sandys (1908-1987) was a British politician, a minister in successive Conservative governments. He was the son-in-law of Sir Winston Churchill.
Sandys was an old-school Tory, educated at Eton College and Magdalen College, Oxford. He entered the diplomatic service in 1930, and became MP for Norwood, a district of London in 1935. In the same year, he married Diana Churchill, daughter of the future prime minister, who would in 1951 give him his first ministerial post, as Minister of Supply. As Minister of Housing in 1954-1957 he introduced the Clean Air Act, and went on to be Minister of Defence. His three years in this post were fraught with difficulty, as he was responsible for cutting costs in the armed services. After his divorce from Diana in 1960, he continued as a minister, holding several different posts until the Conservative government fell from power in 1964.