2003 (MMIII) was a common year that started on a Wednesday, according to the Gregorian calendar. It was the 2003rd year of the Common Era or the Anno Domini designation; the 3rd year of the 3rd millennium and of the 21st century; and the 4th of the 2000s decade.
2003 was designated as:
January
- January 8 – Ron Goodwin, English composer and conductor (b. 1925)
- January 11 – Maurice Pialat, French actor and director (b. 1925)
- January 11 – Richard Simmons, American actor (b. 1913)
- January 12 – Dean Amadon, American ornithologist (b. 1912)
- January 12 – Leopoldo Galtieri, Argentine dictator (b. 1926)
- January 12 – Maurice Gibb, British rock musician (Bee Gees) (b. 1949)
- January 15 – Doris Fisher, American singer-songwriter (b. 1915)
- January 17 – Richard Crenna, American actor (Marooned) (b. 1926)
- January 20 – Al Hirschfeld, American cartoonist (b. 1903)
- January 23 – Nell Carter, African-American singer and actress (b. 1948)
- January 24 – Gianni Agnelli, Italian auto executive (b. 1921)
- January 26 – Valeriy Brumel, Russian athlete (b. 1942)
- January 26 – Hugh Trevor-Roper, Baron Dacre of Glanton, English historian (b. 1917)
- January 27 – Henryk Jablonski, former President of Poland (b. 1909)
- January 29 – Frank Moss, American politician (b. 1911)
February
- February 1 – Michael P. Anderson, American astronaut (b. 1959)
- February 1 – David M. Brown, American astronaut (b. 1956)
- February 1 – Kalpana Chawla, American astronaut (b. 1961)
- February 1 – Laurel Clark, American astronaut (b. 1961)
- February 1 – Rick Husband, American astronaut (b. 1957)
- February 1 – William McCool, American astronaut (b. 1961)
- February 2 – Lou Harrison, American composer (b. 1917)
- February 10 – Edgar de Evia, American photographer (b. 1910)
- February 10 – Ron Ziegler, American White House Press Secretary (b. 1939)
- February 10 – Curt Hennig, American wrestler (b. 1959)
- February 19 – Johnny Paycheck, American singer (b. 1938)
- February 20 – Maurice Blanchot, French philosopher and writer (b. 1907)
- February 20 – Orville Freeman, American politician (b. 1918)
- February 27 – Fred Rogers, American children's television host (b. 1928)
- February 28 – Fidel Sánchez Hernández, President of El Salvador (b. 1917)
- February 28 – Rudolf Kingslake, British lens designer and engineer (b. 1903)
March