- M. Rosaria Piomelli Architectural Collection, 1960/19951
- Marcia Feuerstein Architectural Collection, 1982/19961
- Margaret (Peggy) Cochrane Architectural Collection,, 1951/19901
- Margarete Schutte-Lihotzky Biographical Materials, 1993-20001
- Maria Aubock Architectural Collection, 1980/20061
- Maria Letizia Conforto Architectural Papers, 1982/20001
- Maria Peeva Architectural Collection, 1978/20061
- Maria von der Weppen Architectural Collection, 1978/20011
- Marie-Louise Laleyan Architectural Collection, 1961/20071
- Martha Bil Manevich Architectural Collection, 1963/2012, bulk 1963/19651
- Martha J. Crawford Design Papers, 1961/19741
- Mary Anne Shephard Manuscript, 1847/20161
- Mary Brown Channel Architectural Collection, 1936/2002, bulk 1936/19501
- Mary Lou Drosten Architectural Collection1
- Meeting Minutes of the Art League of Philadelphia and Diary of Art League Member Elsa Marie Hofheinz, 1928/19471