Margaret Beryl Clunies Ross (born 24 April 1942) is a medievalist who was until her retirement in 2009 the McCaughey Professor of English Language and Early English Literature and Director of the Centre for Medieval Studies at the University of Sydney. Her main research areas are Old Norse-Icelandic Studies and the history of their study. Since 1997 she has led the project of editing a new edition of the corpus of skaldic poetry. She has also written articles on Australian Aboriginal rituals and contributed to the Oxford Dictionary of National Biography.
Margaret Tidemann was born in Adelaide, the eldest child of Ernest Phillips Tidemann, a dentist, and his wife Beryl Chudleigh Tidemann, a kindergarten teacher. She attended Walford House, now Walford Church of England Girls' Grammar School, until she was almost 17 and graduated from the University of Adelaide in 1962 with First Class Honours in English. She was influenced to study Old and Middle English and Old Norse by Ralph Elliott, whom the university appointed as she was starting the Honours course. She then completed a B.Litt. at Oxford University on an overseas scholarship from the University of Adelaide and a scholarship from Somerville College. She then worked as a lecturer at St. Hilda's College and Lady Margaret Hall, and in 1968–69 visited the Arnamagnæan Institute in Copenhagen on a travelling fellowship. She became a lecturer at the University of Sydney in 1969, was appointed McCaughey Professor of English Language and Early English Literature in 1990 and in 1997 became Director of the Centre for Medieval Studies. She retired in 2009 and since then has been Honorary Professor in the Medieval and Early Modern Centre and Emeritus Professor of English.