Margaret Dayton (born 1949) is an American politician from Utah. A member of the Republican Party, she served longer in the Utah Legislature than any other woman in Utah history. After serving a decade in the Utah House of Representatives, she unseated an incumbent senator in 2006 and served in that position until June 2018, when she resigned for medical reasons. She represented the 15th Senate District which includes parts of Provo, Orem, Vineyard, Lindon and Pleasant Grove.