Margaret Henderson Floyd (1932 – 18 October 1997) was Professor of Architectural History at Tufts University.
Over the years, she developed detailed knowledge of the architecture of the Boston area and she became deeply involved in historic preservation and often provided expert testimony in an effort to save older buildings from demolition.
She played a key role in the preservation of the Robert Treat Paine Estate in Waltham; she was one of four founding members of Friends of Longfellow House formed to support Longfellow House–Washington's Headquarters National Historic Site.
Floyd was a contributor to the ongoing reassessment of the "standard narrative" of nineteenth-century American architectural history.
Her work on Longfellow, Alden and Harlow argued for a broader appreciation of the wide influence of the architect Henry Hobson Richardson.