| Competition: | Irish League |
| Season: | 1890–91 |
| Winners: | Linfield 1st Irish title |
| League Topscorer: | Robert Hill (20) |
| Biggest Home Win: | Linfield 14–0 Oldpark |
| Biggest Away Win: | Cliftonville 0–8 Linfield Milford 0–8 Glentoran Milford 1–9 Distillery Oldpark 2–10 Ulster |
| Highest Scoring: | Linfield 14–0 Oldpark Linfield 9–5 Ulster |
| Matches: | 56 |
| Total Goals: | 337 |
| Nextseason: | 1891–92 |
The 1890–91 Irish League was the inaugural edition of the Irish League, the highest level of league competition in Irish football organised by the Irish Football Association.
The league comprised 8 teams, and was won by Linfield.
For this season, the league used a double Round-robin format, where teams played each other both home and away once.
| Team | Town | Home Ground | |
|---|---|---|---|
| Clarence | Belfast | Stranmillis | |
| Cliftonville | Belfast | Solitude | |
| Distillery | Belfast | Grosvenor Park | |
| Glentoran | Belfast | King's Field | |
| Linfield | Belfast | Ulsterville | |
| Milford | Armagh | Milford | |
| Oldpark | Belfast | Oldpark | |
| Ulster | Belfast | Ulster Cricket Ground |
| Player | Club | Goals | ||
|---|---|---|---|---|
| 1 | Robert Hill | Linfield | 20 | |
| 2 | John Peden | Linfield | 19 | |
| 3 | Sam Torrans | Linfield | 18 |