1998 Australian motorcycle Grand Prix
The 1998 Australian motorcycle Grand Prix was the thirteenth round of the 1998 Grand Prix motorcycle racing season. It took place on 4 October 1998 at the Phillip Island Grand Prix Circuit.
250 cc classification
125 cc classification
Championship standings after the race (500cc)
Below are the standings for the top five riders and constructors after round thirteen has concluded.
;Riders' Championship standings
;Constructors' Championship standings
| Constructor | Points |
| 1 |  Honda | 320 |
| 2 | Yamaha | 185 |
| 3 | Suzuki | 107 |
| 4 |  Modenas KR3 | 68 |
| 5 |  MuZ | 11 |
- Note: Only the top five positions are included for both sets of standings.
Mick Doohan
Àlex Crivillé
Max Biaggi
Alex Barros