Ireland competed at the 1984 Summer Olympics in Los Angeles, It went from July 28, 1984, to August 12, 1984 United States. 42 competitors, 28 men and 13 women, took part in 35 events in 10 sports.
Medalists
{| class="wikitable sortable" style="font-size:90%"
|-
!Medal
!Name
!Sport
!Event
!Date
|-
| || || Athletics || Men's marathon || 12 August
|}
Archery
In Ireland's third appearance in archery competition at the Olympics, the nation was represented by two women. This included veteran Hazel Greene.
Women's Individual Competition:
- Hazel Greene — 2440 points (→ 20th place)
- Mary Vaughan — 2298 points (→ 39th place)
Athletics
Men's 800 metres
- Marcus O'Sullivan
Men's 1,500 metres
- Marcus O'Sullivan
- Paul Donovan
- Frank O'Mara
Men's 5,000 metres
- Ray Flynn
:* Heat — 13:46.84
:* Semifinals — 13:40.74
:* Final — 13:34.50 (→ 11th place)
Men's 10,000 metres
- John Treacy
:* Qualifying Heat — 28:18.13
:* Final — 28:28.68 (→ 9th place)
Men's Marathon
- John Treacy
:* Final — 2:09:56 (→ Image:Med 2.png Silver Medal)
- Jerry Kiernan
:* Final — 2:12:20 (→ 9th place)
- Dick Hooper
:* Final — 2:24:41 (→ 51st place)
Men's 3,000 m Steeplechase
- Liam O'Brien
Men's Hammer Throw
- Declan Hegarty
:* Qualification — 70.56m (→ did not advance)
- Conor McCullough
:* Qualification — 65.56m (→ did not advance)
Women's 800 metres
:* Caroline O'Shea
Women's 3,000 metres
- Monica Joyce
:* Heat — 8:54.34 (→ did not advance)
- Roisin Smyth
:* Heat — 9.01.69 (→ did not advance)
Women's Marathon
- Regina Joyce
:* Final — 2:37:57 (→ 23rd place)
- Carey May
:* Final — 2:41:27 (→ 28th place)
Women's 400m Hurdles
- Mary Parr
:* Heat — 1:01.66 (→ did not advance)
Women's Discus Throw
- Patricia Walsh
:* Qualification — 54.42m
:* Final — 55.38m (→ 9th place)
Boxing
Men's Light Flyweight (– 48 kg)
- Gerard Hawkins
:* First Round — Bye
:* Second Round — Lost to Salvatore Todisco (ITA), 0:5
Men's Bantamweight (– 54 kg)
- Phillip Sutcliffe
:* First Round — Bye
:* Second Round — Lost to Maurizio Stecca (ITA), 0:5
Canoeing
Men's K1 1000m
- Ian Pringle
Men's K1 500m
- Ian Pringle
Cycling
Five cyclists represented Ireland in 1984.
;Individual road race
- Martin Earley
- Paul Kimmage
- Gary Thomson
- Séamus Downey
;Team time trial
- Philip Cassidy
- Martin Earley
- Paul Kimmage
- Gary Thomson
Equestrianism
Judo
Sailing
Shooting
Swimming
;Women
{| class=wikitable style="font-size:90%;"
|-
!rowspan=2|Athlete
!rowspan=2|Event
!colspan=2|Heat
!colspan=2|Semifinal
!colspan=2|Final
|- style="font-size:95%"
!Time
!Rank
!Time
!Rank
!Time
!Rank
|-align=center
|rowspan=3 align=left|Carol-Ann Heavey
|align=left|100 m freestyle
| 1:01.34
| 33
| colspan=2
| colspan=2 | Did not advance
|-align=center
|align=left|200 m freestyle
| 2:07.75
| 20
| colspan=2
| colspan=2 | Did not advance
|-align=center
|align=left|400 m freestyle
| 4:36.07
| 22
| colspan=2
| colspan=2 | Did not advance
|-align=center
|rowspan=2 align=left|Julie Parkes
|align=left|100 m butterfly
| 1:06.20
| 27
| colspan=2
| colspan=2 | Did not advance
|-align=center
|align=left|200 m butterfly
| 2:20.85
| 21
| colspan=2
| colspan=2 | Did not advance
|}