# List of number-one singles of 1978 (Ireland)

This is a list of singles which have reached number one on the Irish Singles Chart in 1978.
| Week ending | Song | Artist |
| 7 January | "Mull of Kintyre" | Wings |
| 14 January | "Mull of Kintyre" | Wings |
| 21 January | "Mull of Kintyre" | Wings |
| 28 January | "Mull of Kintyre" | Wings |
| 4 February | "Mull of Kintyre" | Wings |
| 11 February | "Mull of Kintyre" | Wings |
| 18 February | "Figaro" | Brotherhood of Man |
| 25 February | "Take a Chance on Me" | ABBA |
| 4 March | "The Rare Auld Times" | Danny Doyle |
| 11 March | "The Rare Auld Times" | Danny Doyle |
| 18 March | "Wuthering Heights" | Kate Bush |
| 25 March | "Wuthering Heights" | Kate Bush |
| 1 April | "Wuthering Heights" | Kate Bush |
| 8 April | "Matchstalk Men and Matchstalk Cats and Dogs" | Brian and Michael |
| 15 April | "Matchstalk Men and Matchstalk Cats and Dogs" | Brian and Michael |
| 22 April | "Matchstalk Men and Matchstalk Cats and Dogs" | Brian and Michael |
| 29 April | "Night Fever" | The Bee Gees |
| 6 May | "Night Fever" | The Bee Gees |
| 13 May | "Night Fever" | The Bee Gees |
| 20 May | "Rivers of Babylon" | Boney M |
| 27 May | "Rivers of Babylon" | Boney M |
| 3 June | "Rivers of Babylon" | Boney M |
| 10 June | "Rivers of Babylon" | Boney M |
| 17 June | "Rivers of Babylon" | Boney M |
| 24 June | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 1 July | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 8 July | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 15 July | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 22 July | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 29 July | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 5 August | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 12 August | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 19 August | "Substitute" | Clout |
| 26 August | "You're the One That I Want" | John Travolta and Olivia Newton-John |
| 2 September | "Three Times a Lady" | The Commodores |
| 9 September | "Three Times a Lady" | The Commodores |
| 16 September | "Three Times a Lady" | The Commodores |
| 23 September | "Summer Night City" | ABBA |
| 30 September | "One Day at a Time" | Gloria |
| 7 October | "Summer Nights" | John Travolta and Olivia Newton-John |
| 14 October | "Summer Nights" | John Travolta and Olivia Newton-John |
| 21 October | "Summer Nights" | John Travolta and Olivia Newton-John |
| 28 October | "Summer Nights" | John Travolta and Olivia Newton-John |
| 4 November | "Sandy" | John Travolta |
| 11 November | "One Day at a Time" | Gloria |
| 18 November | "Hopelessly Devoted to You" | Olivia Newton-John |
| 25 November | "Mary's Boy Child – Oh My Lord" | Boney M |
| 2 December | "Mary's Boy Child – Oh My Lord" | Boney M |
| 9 December | "Mary's Boy Child – Oh My Lord" | Boney M |
| 16 December | "Mary's Boy Child – Oh My Lord" | Boney M |
| 23 December | "Mary's Boy Child – Oh My Lord" | Boney M |
| 30 December | "Mary's Boy Child – Oh My Lord" | Boney M |
* 17 Number Ones
* Most weeks at No. 1 (artist): John Travolta (14), Olivia Newton-John (14)
* Most weeks at No. 1 (song): "You're The One That I Want" - John Travolta and Olivia Newton-John (9)
* Most No.1s: John Travolta (3), Olivia Newton-John (3)
* 4 songs from the film Grease reached No. 1: "You're The One That I Want", "Summer Nights", "Sandy" and "Hopelessly Devoted to You"