BDO may refer to:

• Ballon d'Or, an annual football award
• Banco de Oro, one of the largest banks in the Philippines
• Barton, Durstine & Osborn, the former name of advertising agency BBDO
• BDO Global, the world's fifth-largest accountancy network
• BDO USA
• Behavior Detection Officer, part of the Transportation Security Administration
• Big Day Out, an annual music festival held in Australia and New Zealand
• Big Dumb Object, a term used in science fiction
• Black Desert Online, an MMORPG
• Block Development Officer, the official in charge of an administrative division (block) of some South Asian countries
• British Darts Organisation (now defunct), former governing body of British darts
• Business Depot Ogden, the former Defense Depot Ogden Utah converted into a business park
• Butanediol, especially 1,4-Butanediol, an organic chemical compound and psychoactive drug
• League of German Officers (German: Bund Deutscher Offiziere), an association of German prisoners of war in the Soviet Union
• The IATA code of Husein Sastranegara International Airport, the airport serving Bandung, Indonesia

• <bdo></bdo>, an HTML element for bi-directional override, see HTML element § bdo