Sidney Montagu may refer to:
Sidney Montagu (MP, died 1644), English member of parliament (MP) Sidney Wortley Montagu (1650–1727), British coal-owner and MP Sidney Montagu, 11th Duke of Manchester (1929–1985), British hereditary peer
See also Sydney Montagu Samuel (1848–1884), English journalist, librettist, financier, and communal worker