Maçons notáveis – O
José María Obando (1795-1861), Colombian President and general
- Dositej Obradović (1742–1811), Serbian author, philosopher, linguist, polyglot and the first minister of education of Serbia.
- Mihailo Obrenović III, Prince of Serbia,
- William O’Brien, 4th Earl of Inchiquin (1700 – 18 July 1777), KB Irish peer and politician. Grand Master of the Grand Lodge of England (Moderns) in 1726.
- Daniel O’Connell, Irish political figure, Lodge No. 189, Dublin, in 1797
- Hans Christian Oersted (1777–1851), Danish physicist and chemist who discovered that electric currents create magnetic fields.
- Bernardo O’Higgins, South American revolutionary leader and first Chilean head of state as Captain General
- Harris R. Oke (1891–1940), was a wounded veteran of World War 1 who became Colonial Secretary, The Gambia, British West Africa (1934–1940) and served as its Acting Governor and Commander-in-Chief for six extended periods between 1934 and 1940
- Ransom E. Olds, Automotive pioneer and founder of Oldsmobile. Capitol Lodge No. 66, Lansing, MI
- Shaquille O’Neal, NBA basketball player. Made a “Mason at sight” by the Most Worshipful Prince Hall Grand Lodge of Massachusetts F&AM, member of Widow’s Son Lodge No. 28 in Boston
- William Onslow, 4th Earl of Onslow, British politician
- Camilo Osías, President of the Senate of the Philippines.
- William Dillon Otter, Canadian General. Initiated in Ionic Lodge, No. 25, Toronto in February 1869
- Derwyn Owen, Archbishop of Toronto, and Primate of the Anglican Church of Canada, Ionic Lodge No 25, Toronto.
Fonte: Wikipedia