Margaret Sinclair

Margaret Sinclair may refer to:

• Margaret Sinclair (nun) (1900–1925), Scottish Roman Catholic nun
• Margaret P. Sinclair (1950–2012), Canadian mathematics educator
• The maiden name of Margaret Trudeau
• Margaret Sinclair, Countess of Caithness, see William Sinclair, 2nd Earl of Caithness
• Margaret Sinclair Ogden (1909–1988), American historian and lexicographer