| Season: | 2005–06 |
| Stadium: | San Mamés |
| Manager: | José Luis Mendilibar (to 31 October) Javier Clemente (from 31 October) |
| Mgrtitle: | Head coach |
| Chrtitle: | President |
| Chairman: | Fernando Lamikiz Garai |
| League: | La Liga |
| League Result: | 12th |
| Cup1: | Copa del Rey |
| Cup1 Result: | Round of 16 |
| Cup2: | UEFA Intertoto Cup |
| Cup2 Result: | Round 2 |
| League Topscorer: | Aritz Aduriz (6 goals)[1] |
| Season Topscorer: | Aritz Aduriz (6 goals) |
| Prevseason: | 2004–05 |
| Nextseason: | 2006–07 |
The 2005–06 season was the 105th season in Athletic Bilbao's history and their 75th consecutive season in La Liga, the top division of Spanish football.