List of Ultratop 50 number-one singles of 2003
# List of Ultratop 50 number-one singles of 2003

These hits topped the Ultratop 50 charts in 2003 (see 2003 in music).

| Issue Date | Artist | Title |
| - | - | - |
| January 4 | Eminem | "Lose Yourself" |
| January 11 | Eminem | "Lose Yourself" |
| January 18 | Eminem | "Lose Yourself" |
| January 25 | Jasper Steverlinck & Steven & Stijn Kolacny | "Life on Mars?" |
| February 1 | Jasper Steverlinck & Steven & Stijn Kolacny | "Life on Mars" |
| February 8 | Jasper Steverlinck & Steven & Stijn Kolacny | "Life on Mars" |
| February 15 | Jasper Steverlinck & Steven & Stijn Kolacny | "Life on Mars" |
| February 22 | Jasper Steverlinck & Steven & Stijn Kolacny | "Life on Mars" |
| March 1 | Jasper Steverlinck & Steven & Stijn Kolacny | "Life on Mars" |
| March 8 | Jasper Steverlinck & Steven & Stijn Kolacny | "Life on Mars" |
| March 15 | Jasper Steverlinck & Steven & Stijn Kolacny | "Life on Mars" |
| March 22 | Céline Dion | "I Drove All Night" |
| March 29 | Spring | "Spring" |
| April 5 | Spring | "Spring" |
| April 12 | Spring | "Spring" |
| April 19 | Spring | "Spring" |
| April 26 | Spring | "Spring" |
| May 3 | Spring | "Spring" |
| May 10 | Spring | "Spring" |
| May 17 | Spring | "Spring" |
| May 24 | Peter Evrard | "For You" |
| May 31 | Peter Evrard | "For You" |
| June 7 | Peter Evrard | "For You" |
| June 14 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| June 21 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| June 28 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| July 5 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| July 12 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| July 19 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| July 26 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| August 2 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| August 9 | The Underdog Project & The Sunclub | "Summer Jam 2003" |
| August 16 | Wim Soutaer | "Allemaal" |
| August 23 | Wim Soutaer | "Allemaal" |
| August 30 | Brahim | "Turn the Music Up" |
| September 6 | Brahim | "Turn the Music Up" |
| September 13 | Wim Soutaer | "Allemaal" |
| September 20 | Brahim | "Turn the Music Up" |
| September 27 | Lumidee | "Never Leave You (Uh Oooh, Uh Oooh)" |
| October 4 | The Black Eyed Peas | "Where Is the Love?" |
| October 11 | The Black Eyed Peas | "Where Is the Love?" |
| October 18 | The Black Eyed Peas | "Where Is the Love?" |
| October 25 | The Black Eyed Peas | "Where Is the Love?" |
| November 1 | Sarah & Koen Wauters | "You Are the Reason" |
| November 8 | Sarah & Koen Wauters | "You Are the Reason" |
| November 15 | Sarah & Koen Wauters | "You Are the Reason" |
| November 22 | Sarah & Koen Wauters | "You Are the Reason" |
| November 29 | Sarah & Koen Wauters | "You Are the Reason" |
| December 6 | Natalia | "I've Only Begun to Fight" |
| December 13 | Natalia | "I've Only Begun to Fight" |
| December 20 | The Black Eyed Peas | "Shut Up" |
| December 27 | The Black Eyed Peas | "Shut Up" |
