Robert Morrison Maciver (April 17, 1882 – June 15, 1970) was a Scottish-born American sociologist.
Robert Morrison MacIver was born in Stornoway, Isle of Lewis, Scotland on April 17, 1882 to Donald MacIver, a general merchant and tweed manufacturer, and Christina MacIver (née Morrison). On 14 August 1911 he married Elizabeth Marion Peterkin. They went on to have three children: Ian Tennant Morrison, Christina Elizabeth, and Donald Gordon.)
He received degrees from the University of Edinburgh (M.A. 1903; D.Ph. 1915), the University of Oxford (B.A. 1907), and Columbia University (Litt.E. 1929 and Harvard (1936). In his rather long period of formal education, he had never made any academically supervised study of sociology. His work in that field was distinguished by his acumen, his philosophical understanding, and extensive study of the major pioneering works of Durkheim, Toennies, Max and Alfred Weber, Simmel and others in the British Museum Library in London, while resident as a student in Oxford.
He was a university Lecturer in Political Science (1907) and sociology (1911) at the University of Aberdeen. He left Aberdeen in 1915 for a post at the University of Toronto where he was Professor of Political Science and later Head of Department from 1922 to 1927. In 1927 he accepted an invitation from Barnard College of Columbia University in New York City, where he became Professor of Social Science from 1927 to 1936. He was subsequently named Lieber Professor of Political Science and Sociology at Columbia University and taught there from 1929 to 1950. He was President, beginning in 1963, and then Chancellor of The New School for Social Research (1965-66).
MacIver was Vice-Chairman of the Canada War Labor Board from 1917 to 1918. He was a Fellow of the Royal Society of Canada, the American Academy of Arts and Sciences, and the American Philosophical Society. He was a member of the American Sociological Society, and was elected as its 30th President in 1940. He was a member of the Institut International de Sociologie and of Phi Beta Kappa.