1989–90 Courage League National Division One
| 1989–90 Courage League National Division One | |
|---|---|
| Countries | England |
| Date | 9 September 1989 – 28 April 1990 |
| Champions | Wasps (1st title) |
| Runners-up | Gloucester |
| Relegated | Bedford |
| Matches played | 66 |
The 1988–89 Courage League National Division One was the third season of the first tier of the English league system, currently known as the Gallagher Premiership. Bath were the defending champions while new sides Saracens and Bedford were promoted from the 1988–89 Courage League National Division Two. Each team played each other once.
A very competitive league was won by Wasps, pipping Gloucester to the title by just one point, with Bath and Saracens not far behind in 3rd and 4th spot. Due to the league increasing from 12 to 13 teams for the following season, Bedford were the only side to be relegated, losing all 11 fixtures to finish bottom of the table and drop down to the 1990–91 Courage League National Division Two.