List of number-one singles of 1977 (Ireland)
This is a list of singles which have reached number one on the Irish Singles Chart in 1977.
| Week ending | Song | Artist |
| 1 January | When a Child is Born | Johnny Mathis |
| 8 January | If You Leave Me Now | Chicago |
| 15 January | If You Leave Me Now | Chicago |
| 22 January | Living Next Door to Alice | Smokie |
| 29 January | Living Next Door to Alice | Smokie |
| 5 February | Don't Cry for Me Argentina | Julie Covington |
| 12 February | Don't Cry for Me Argentina | Julie Covington |
| 19 February | Don't Cry for Me Argentina | Julie Covington |
| 26 February | When I Need You | Leo Sayer |
| 5 March | When I Need You | Leo Sayer |
| 12 March | When I Need You | Leo Sayer |
| 19 March | Chanson D'Amour | Manhattan Transfer |
| 26 March | Chanson D'Amour | Manhattan Transfer |
| 2 April | Chanson D'Amour | Manhattan Transfer |
| 9 April | Knowing Me, Knowing You | ABBA |
| 16 April | Knowing Me, Knowing You | ABBA |
| 23 April | Knowing Me, Knowing You | ABBA |
| 30 April | Knowing Me, Knowing You | ABBA |
| 7 May | Knowing Me, Knowing You | ABBA |
| 14 May | It's Nice To Be In Love Again | The Swarbriggs  |
| 21 May | Have I the Right? | Dead End Kids |
| 28 May | Have I the Right? | Dead End Kids |
| 4 June | Have I the Right? | Dead End Kids |
| 11 June | Big Tom is Still the King | Susan McCann |
| 18 June | Big Tom is Still the King | Susan McCann |
| 25 June | Back Home | Dickie Rock |
| 2 July | Back Home | Dickie Rock |
| 9 July | Back Home | Dickie Rock |
| 16 July | Back Home | Dickie Rock |
| 23 July | Sam | Olivia Newton-John |
| 30 July | Sam | Olivia Newton-John |
| 6 August | When Benji Wrapped his Tractor Round the Old Oak Tree | Brendan Grace |
| 13 August | When Benji Wrapped his Tractor Round the Old Oak Tree | Brendan Grace |
| 20 August | Daddy's Little Girl | Brendan Quinn |
| 27 August | Angelo | Brotherhood of Man |
| 3 September | I Need You | Joe Dolan |
| 10 September | Way Down | Elvis Presley |
| 17 September | I Need You | Joe Dolan |
| 24 September | Nobody Does it Better | Carly Simon |
| 1 October | Way Down | Elvis Presley |
| 8 October | Silver Lady | David Soul |
| 15 October | Silver Lady | David Soul |
| 22 October | Silver Lady | David Soul |
| 29 October | Silver Lady | David Soul |
| 5 November | Yes Sir I Can Boogie | Baccara |
| 12 November | Calling Occupants of Interplanetary Craft | The Carpenters |
| 19 November | Calling Occupants of Interplanetary Craft | The Carpenters |
| 26 November | Belfast | Boney M |
| 3 December | Rockin' All Over the World | Status Quo |
| 10 December | Mull of Kintyre | Wings |
| 17 December | Mull of Kintyre | Wings |
| 24 December | Mull of Kintyre | Wings |
| 31 December | Mull of Kintyre | Wings |
- 24 Number Ones
- Most weeks at No.1 : ABBA
- Most weeks at No.1 : "Knowing Me, Knowing You" - ABBA
- Most No.1s: all artists 1 Number One each