03
03 may refer to:

The year 2003, or any year ending with 03
The month of March
3 (number)

Music
03 (Twelve album), 2007
03 (Son of Dave album), 2008
03 (Urban Zakapa album), 2013

Other uses
03 numbers, a non-geographic telephone number range in the UK
The number of the French department Allier
The occupational field designator for U.S. Marine Corps Infantry
Tokyo Metro 03 series

See also
O3 (disambiguation)
3 (disambiguation)