This is a list of singles which have reached number one on the Irish Singles Chart in 1981.
| Week ending | Song | Artist |
|---|---|---|
| 3 January | " There's No-one Quite Like Grandma" | St Winifred's School Choir |
| 10 January | " (Just Like) Starting Over" | John Lennon |
| 17 January | ||
| 24 January | ||
| 31 January | " Imagine" | |
| 7 February | " Woman" | |
| 14 February | ||
| 21 February | ||
| 28 February | " Shaddap You Face" | Joe Dolce |
| 7 March | ||
| 14 March | ||
| 21 March | " Vienna" | Ultravox |
| 28 March | "More and More" | Joe Dolan |
| 4 April | " This Ole House" | Shakin' Stevens |
| 11 April | ||
| 18 April | ||
| 25 April | " Making Your Mind Up" | Bucks Fizz |
| 2 May | ||
| 9 May | " Stars on 45" | Starsound |
| 16 May | ||
| 23 May | " You Drive Me Crazy" | Shakin' Stevens |
| 30 May | ||
| 6 June | ||
| 13 June | ||
| 20 June | ||
| 27 June | ||
| 4 July | " One Day in Your Life" | Michael Jackson |
| 11 July | ||
| 18 July | " When You Were Sweet Sixteen" | The Fureys and Davy Arthur |
| 25 July | " The Streets of New York" | Wolfe Tones |
| 1 August | ||
| 8 August | ||
| 15 August | " Green Door" | Shakin' Stevens |
| 22 August | ||
| 29 August | ||
| 5 September | ||
| 12 September | " A Bunch of Thyme" | Foster and Allen |
| 19 September | " Japanese Boy" | Aneka |
| 26 September | " Prince Charming" | Adam and the Ants |
| 3 October | ||
| 10 October | " Hands Up (Give Me Your Heart)" | Ottawan |
| 17 October | ||
| 24 October | " It's My Party" | Dave Stewart and Barbara Gaskin |
| 31 October | ||
| 7 November | ||
| 14 November | ||
| 21 November | " Every Little Thing She Does is Magic" | The Police |
| 28 November | " Begin the Beguine" | Julio Iglesias |
| 5 December | ||
| 12 December | ||
| 19 December | " Don't You Want Me" | The Human League |
| 26 December | " One of Us" | ABBA |
- 24 Number Ones
- Most weeks at No.1 (song): "You Drive Me Crazy" - Shakin' Stevens (6)
- Most weeks at Number One (artist): Shakin' Stevens (13)
- Most No.1s: John Lennon, Shakin' Stevens (3)