This is a list of singles which have reached number one on the Irish Singles Chart in 1985.
| Week ending | Song | Artist | Ref. | |
|---|---|---|---|---|
| 5 January | "Do They Know It's Christmas?" | Band Aid | ||
| 12 January | ||||
| 19 January | ||||
| 26 January | "I Want to Know What Love Is" | Foreigner | ||
| 2 February | ||||
| 9 February | "I Know Him So Well" | Elaine Paige and Barbara Dickson | ||
| 16 February | ||||
| 23 February | [1] | |||
| 2 March | ||||
| 9 March | ||||
| 16 March | "You Spin Me Round (Like a Record)" | Dead or Alive | ||
| 23 March | "Easy Lover" | Philip Bailey and Phil Collins | ||
| 30 March | "Show Some Concern" | The Concerned | ||
| 6 April | ||||
| 13 April | "We are the World" | USA for Africa | ||
| 20 April | ||||
| 27 April | ||||
| 4 May | ||||
| 11 May | "The Unforgettable Fire" | U2 | ||
| 18 May | ||||
| 25 May | "19" | |||
| 1 June | ||||
| 8 June | "I'm on Fire" / "Born in the U.S.A." | Bruce Springsteen | ||
| 15 June | ||||
| 22 June | "You'll Never Walk Alone" | The Crowd | ||
| 29 June | "Frankie" | Sister Sledge | ||
| 6 July | ||||
| 13 July | ||||
| 20 July | ||||
| 27 July | "Axel F" | |||
| 3 August | "There Must Be an Angel (Playing with My Heart)" | Eurythmics | ||
| 10 August | "Into the Groove" | Madonna | ||
| 17 August | ||||
| 24 August | ||||
| 31 August | "I Got You Babe" | UB40 with Chrissie Hynde | ||
| 7 September | ||||
| 14 September | "Dancing in the Street" | David Bowie and Mick Jagger | ||
| 21 September | ||||
| 28 September | "Holding Out for a Hero" | Bonnie Tyler | ||
| 5 October | "Part-Time Lover" | Stevie Wonder | ||
| 12 October | "If I Was" | Midge Ure | ||
| 19 October | "The Power of Love" | |||
| 26 October | ||||
| 2 November | ||||
| 9 November | ||||
| 16 November | "Nikita" | Elton John | ||
| 23 November | "A Good Heart" | Feargal Sharkey | ||
| 30 November | ||||
| 7 December | "I'm Your Man" | Wham! | ||
| 14 December | "Separate Lives" | Phil Collins and Marilyn Martin | ||
| 21 December | "Saving All My Love for You" | Whitney Houston | ||
| 28 December | "Thank You Very Much Mr. Eastwood" | Dermot Morgan |