This is a list of the U.S. Billboard magazine Mainstream Top 40 number-one songs of 2003.
During 2003, a total of 16 singles hit number-one on the charts.
| Issue Date | Song | Artist(s) | Ref |
|---|---|---|---|
| January 4 | "Lose Yourself" | Eminem | [1] |
| January 11 | "Beautiful" | Christina Aguilera | [2] |
| January 18 | [3] | ||
| January 25 | [4] | ||
| February 1 | [5] | ||
| February 8 | "I'm with You" | Avril Lavigne | [6] |
| February 15 | [7] | ||
| February 22 | [8] | ||
| March 1 | [9] | ||
| March 8 | "All I Have" | Jennifer Lopez featuring LL Cool J | [10] |
| March 15 | [11] | ||
| March 22 | [12] | ||
| March 29 | [13] | ||
| April 5 | "In da Club" | 50 Cent | [14] |
| April 12 | [15] | ||
| April 19 | [16] | ||
| April 26 | [17] | ||
| May 3 | "When I'm Gone" | 3 Doors Down | [18] |
| May 10 | "Ignition" | R. Kelly | [19] |
| May 17 | "Rock Your Body" | Justin Timberlake | [20] |
| May 24 | [21] | ||
| May 31 | [22] | ||
| June 7 | [23] | ||
| June 14 | "Bring Me to Life" | Evanescence featuring Paul McCoy | [24] |
| June 21 | [25] | ||
| June 28 | "Miss Independent" | Kelly Clarkson | [26] |
| July 5 | [27] | ||
| July 12 | [28] | ||
| July 19 | [29] | ||
| July 26 | [30] | ||
| August 2 | [31] | ||
| August 9 | "Where Is the Love?" | The Black Eyed Peas | [32] |
| August 16 | "Crazy in Love" | Beyoncé featuring Jay-Z | [33] |
| August 23 | "Where Is the Love?" | The Black Eyed Peas | [34] |
| August 30 | [35] | ||
| September 6 | [36] | ||
| September 13 | [37] | ||
| September 20 | [38] | ||
| September 27 | [39] | ||
| October 4 | "Shake Ya Tailfeather" | Nelly, P. Diddy and Murphy Lee | [40] |
| October 11 | [41] | ||
| October 18 | [42] | ||
| October 25 | "Here Without You" | 3 Doors Down | [43] |
| November 1 | [44] | ||
| November 8 | "Baby Boy" | Beyoncé featuring Sean Paul | [45] |
| November 15 | "Here Without You" | 3 Doors Down | [46] |
| November 22 | [47] | ||
| November 29 | [48] | ||
| December 6 | [49] | ||
| December 13 | "Hey Ya!" | OutKast | [50] |
| December 20 | [51] | ||
| December 27 | [52] |
