2003–04 Top League
| 2003–04 Top League | |
|---|---|
| Countries | Japan |
| Date | |
| Champions | Kobelco Steelers |
| Runners-up | Toshiba Brave Lupus |
The 2003–04 Top League was the first season of Japan's domestic rugby union competition, the Top League. Toshiba Brave Lupus won the league by finishing on top of the round-robin competition.
Toshiba Brave Lupus lost the final of Microsoft Cup to NEC Green Rockets, but the cup was considered a separate competition to the Top League prior to 2007.