The 1998–1999 English Premiership (called the Allied Dunbar Premiership for sponsorship reasons) was the 12th season of the league at the top of the English rugby union pyramid, the Premiership (rugby union).

This was the second season under the sponsorship of Allied Dunbar.

The league was expanded to include 14 teams instead of 12, with London Scottish, West Hartlepool and Bedford Blues being elected to the premiership.

Note: Flags to the left of player names indicate national team as has been defined under World Rugby eligibility rules, or primary nationality for players who did not yet earn international senior caps.

Players may hold one or more non-WR nationalities.