

She holds a Bachelor of Philosophy (BPhil) degree in politics from St Hilda's College, Oxford, and a Doctor of Philosophy (DPhil) degree from St Antony's College, Oxford. MacMillan received a Bachelor of Arts (BA) degree in history from the University of Toronto, where she attended Trinity College. Her maternal grandmother, Lady Olwen Carey Evans, was a daughter of David Lloyd George, Prime Minister of the United Kingdom, and his first wife, Dame Margaret Lloyd George. The senior Evans served as personal physician to Rufus Isaacs, 1st Marquess of Reading, during the latter's term as Viceroy of India (1921–26). Carey Evans of the Indian Medical Service. Her maternal grandfather was Major Sir Thomas J. Margaret MacMillan was born to Dr Robert Laidlaw MacMillan and Eluned Carey Evans on December 23, 1943. MacMillan was the 2018 Reith lecturer, giving five lectures across the globe on the theme of war under the title The Mark of Cain, the tour taking in London, York, Beirut, Belfast, and Ottawa. MacMillan is an expert on history and international relations.

She is former provost of Trinity College, Toronto, and professor of history at the University of Toronto and previously at Ryerson University (now Toronto Metropolitan University).

Margaret Olwen MacMillan, OM CC CH FRSL FRSC FBA FRCGS (born December 23, 1943) is a Canadian historian and professor at the University of Oxford. Peacemakers: The Paris Peace Conference of 1919 and Its Attempt to End War (2001)
