2005-06 Adelaide United FC season–

The 2005–06 Adelaide United FC season was the club's second season since its establishment in 2003. The club participated in the A-League for the first time after the National Soccer League was replaced.

Continuing their good form from the final season of the NSL, Adelaide United finished as Premiers in the inaugural season of the Hyundai A-League. Qu Shengqing, Fernando Rech and Carl Veart shared the goal scoring with 7 a piece.

The Reds were bundled out of the finals race in straight sets losing to Sydney FC in the two leg semi final and then Central Coast Mariners 1–0 in the preliminary final at Hindmarsh.

FIFA Club World Cup Qualification
Seven of the A-League clubs participated in a short tournament to find who would be Australia's representative at the FIFA Club World Cup in December. The New Zealand Knights did not compete, and Perth Glory received a bye into the second round.

End of season awards

 * Club Champion:
 * Carl Veart
 * Player's Player:
 * Michael Valkanis
 * Top goalscorer:
 * Carl Veart, Fernando Rech and Shengqing Qu (7)
 * Best Team Man:
 * Matthew Kemp
 * Rising Star:
 * Adam van Dommele