• Oscar
• O’Shea, Milo (1926-2013)
• Oskar Reinhart Collection (Winterthur)
• Oslo (Norway)
• Osny (France)
• Ospedale degli Innocenti (Firenze)
• Ostend (Belgium)
• Ostermundigen (Switzerland)
• Österreichische Galerie Belvedere (Vienna)
• Ostrava (Czech Republic)
• Ostrich