Lorna Marsden, CM OOnt (born March 6, 1942) is a Canadian sociologist, academic administrator, and former Senator.

She was the Associate Dean of the Graduate School and the Vice-Provost (Arts and Sciences) at the University of Toronto.

She attended the founding meeting of the National Action Committee on the Status of Women in April, 1972 and served as President of NAC from 1975-77.She was active in the Ontario Committee on the Status of Women from 1971 and is co-author of the book about that feminist group, White Gloves Off (2018).

In 1984, she was appointed by Prime Minister Pierre Trudeau to the Senate representing the senatorial division of Toronto-Taddle Creek, Ontario.

She was named a YWCA Women of Distinction in 2003 and was made an Honorary Alumnae of the University of Victoria in 2003.