| Competition: | Turkish Second League Category A |
| Season: | 2005–06 |
| Winners: | Bursaspor |
| Promoted: | Bursaspor, Antalyaspor, Sakaryaspor |
| Relegated: | Mersin İdman Yurdu, Yozgatspor, Çanakkale Dardanelspor |
| League Topscorer: | Taner Demirbaş Ufuk Ateş (20) |
| Matches: | 307 |
| Total Goals: | 811 |
| Prevseason: | 2004–05 |
| Nextseason: | 2006–07 |
The 2005–06 Turkish Second League Category A (also known as Iddaa League A due to sponsoring reasons) was the second-level football league of Turkey and the 43rd season since its establishment in 1963–64. At the end of the season, in which 18 teams competed in a single group, Bursaspor and Antalyaspor, which finished the league in the first two places, and the play-off winner Sakaryaspor were promoted to the upper league, while Mersin İdman Yurdu, Yozgatspor and Çanakkale Dardanelspor, which were in the last three places, were relegated.[1]
Promotion play-offs were organized in 19 Mayıs Stadium in Ankara between May 20 and May 24
| Rank | Player | Club | Goals | |
|---|---|---|---|---|
| 1 |  Taner Demirbaş | Sakaryaspor | 20 | |
| Ufuk Ateş | Altay | 20 | ||
| 3 | Coşkun Birdal | Antalyaspor | 18 | |
| 4 | Fazlı Ulusoy | Altay | 15 | |
| 5 | Erol Kapusuz | İstanbul BB | 13 | |
| Mehmet Yıldız | İstanbulspor | 13 | ||
| Serdar Sinik | Türk Telekom | 13 | ||
| 8 | Murat Bölükbaş | Sakaryaspor | 12 | |
| Özgür Karakaya | Kocaelispor | 12 | ||
| 10 | Hakan Keleş | Antalyaspor | 11 |