Marion Isadore Manley FAIA (April 29, 1893 – February 1984)[1] was an American architect, the second woman registered to practice in Florida, and the thirteenth female member of the American Institute of Architects.

After she graduated from the University of Illinois, she moved to Miami, Florida, in 1917 where she practised for almost 50 years, contributing to the development of the urban environment.

Her commissions also included small Spanish-style houses in the 1920s, work on Miami's U.S. Post Office and Federal Building in the 1930s, the masterplan for the Coral Gables, Florida campus of the University of Miami with Robert Law Weed and its first large classroom building in the 1940s, many "tropical modern" houses, the University of Miami's Jerry Herman Ring Theatre, and the shell for the Asolo Theater at the Ringling Museum in the 1950s.

[3] Manley's work encompassed vernacular architecture in residential and public buildings as she drew on local materials suitable for use in the tropical climate of South Florida.

She received the Gold Medal Award in 1973 from the Florida Association of the American Institute of Architects.