Charles O'Brien

• Charles O'Brien, 5th Viscount Clare
• Charles O'Brien, 6th Viscount Clare, Irish military officer in French service
• Charles O'Brien, 7th Viscount Clare
• Charles O'Brien (colonial administrator), British Governor of the Seychelles and Barbados
• Charles O'Brien (cricketer), Australian cricketer
• Charles F. X. O'Brien, United States Representative from New Jersey
• Charles H. O'Brien, State Senator and judge from Tennessee, United States
• Charles M. O'Brien, Member of the Legislative Assembly of Alberta, Canada
• Charles P. O'Brien, American research scientist
• Charlie O'Brien, retired American baseball player
• Charlie O'Brien (racing driver), Australian racing driver
• Charles O'Brien (unionist), American labor union organizer