The 2005 Australian motorcycle Grand Prix was the fifteenth round of the 2005 MotoGP Championship.

It took place on the weekend of 13–15 October 2005 at the Phillip Island Grand Prix Circuit.

It was also the final victory for Valentino Rossi at Phillip Island until the 2014 event.

Below are the standings for the top five riders and constructors after round fifteen has concluded.

[9]