03 may refer to:

• The year 2003, or any year ending with 03
• The month of March
• 3 (number)
• 03 (Twelve album), 2007
• 03 (Son of Dave album), 2008
• 03 numbers, a non-geographic telephone number range in the UK
• The number of the French department Allier

See also

• O3 (disambiguation)
• 3 (disambiguation)

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