| Competition: | League of Ireland |
| Season: | 1955–56 |
| Winners: | St Patrick's Athletic (3rd title) |
| League Topscorer: | Shay Gibbons (21 goals) |
| Biggest Home Win: | Shelbourne 7–1 Limerick Waterford 7–1 Limerick Shamrock Rovers 6–0 Transport |
| Biggest Away Win: | Transport 1–6 Waterford |
| Highest Scoring: | Waterford 8–3 Transport |
| Matches: | 132 |
| Total Goals: | 520 |
| Prevseason: | 1954–55 |
| Nextseason: | 1956–57 |
The 1955–56 League of Ireland was the 35th season of senior football in the Republic of Ireland.
St Patrick's Athletic were the defending champions.
No new teams were elected to the League.
St Patrick's Athletic won their third title.
| Rank | Player | Club | Goals |
|---|---|---|---|
| 1 | Shay Gibbons | St Patrick's Athletic | 21 |
| 2 | Paddy Ambrose | Shamrock Rovers | 20 |
| 3 | Paddy O'Rourke | St Patrick's Athletic | 17 |
| 4 | Gerry Malone | Shelbourne | 15 |
| 5 | Johnny Armstrong | Sligo Rovers | 14 |
| 6 | Jack Walsh | 12 | |
| 7 | Jack Fitzgerald | Waterford | 11 |
| Mick Lipper | Limerick | ||
| Sonny Price | Waterford | ||
| 10 | Francie Callan | Dundalk | 10 |
| Eddie Doran | Evergreen United | ||