This is a list of singles which have reached number one on the Irish Singles Chart in 1981.
| Week ending | Song | Artist | Ref. |
|---|---|---|---|
| 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" | [1] | |
| 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 | |