Mary Dingman (April 9, 1875 – March 21, 1961) was an American social and peace activist, who served as a staff member of the YWCA USA and World YWCA to develop programs to improve the working conditions of women and children in the workforce. Traveling throughout the world, beginning in 1917, she organized programs in the United States, Europe, and Asia. In 1931, she joined the pacifist movement and serve as chair of the Peace and Disarmament Committee of the Women's International Organisations for a decade. Turning her attention to the need for world cooperation, she pressed for the formalization of the United Nations, serving as a delegate to the first United Nations conference. She was employed as a child welfare advocate by the UN from 1948 until her retirement in 1954.