| Competition: | Druga HNL |
| Season: | 2005–06 |
| Winners: | Belišće (North Division) Šibenik (South Division) |
| Promoted: | Šibenik |
| Relegated: | Grafičar Vodovod Metalac Osijek Graničar Županja Slavonija Požega Dilj Mladost Molve Novalja Segesta Karlovac |
| Prevseason: | 2004–05 |
| Nextseason: | 2006–07 |
The 2005–06 Druga HNL (also known as 2. HNL) season was the 15th season of Croatia's second level football since its establishment in 1992. The league was contested in two regional groups (North Division and South Division), with 12 clubs each. This was the last season under that format as the following season featured united Druga HNL with 16 teams. Mosor were originally relegated but were reprieved so that the following season has 16 clubs.
| Club | City / Town | Stadium | Capacity | |
|---|---|---|---|---|
| Belišće | Belišće | Gradski stadion Belišće | 4,000 | |
| Bjelovar | Bjelovar | Gradski stadion Bjelovar | 4,000 | |
| Čakovec | Čakovec | Stadion SRC Mladost | 8,000 | |
| Dilj | Vinkovci | Stadion NK Dilj | 3,000 | |
| Grafičar Vodovod | Osijek | Podgrađe | 4,500 | |
| Graničar Županja | Županja | u Spomen "Prve Nogometne Lopte" | 2,000 | |
| Koprivnica | Koprivnica | Gradski stadion Koprivnica | 4,000 | |
| Marsonia | Slavonski Brod | Gradski Stadion uz Savu | 10,000 | |
| Metalac Osijek | Osijek | SC Bikara | 1,500 | |
| Mladost Molve | Molve | Petar Focić Stadium | 1,000 | |
| Slavonija Požega | Požega | Gradski stadion Požega | 4,000 | |
| Vukovar '91 | Vukovar | Gradski stadion Borovo Naselje | 6,000 |
| Club | City / Town | Stadium | Capacity | |
|---|---|---|---|---|
| Croatia Sesvete | Sesvete | Stadion ŠRC Sesvete | 3,500 | |
| Hrvatski Dragovoljac | Zagreb | Stadion NŠC Stjepan Spajić | 5,000 | |
| Imotski | Imotski | Stadion Gospin dolac | 4,000 | |
| Karlovac | Karlovac | Stadion 13. srpanj | 12,000 | |
| Mosor | Žrnovnica | Stadion Pricviće | 3,000 | |
| Naftaš Ivanić Grad | Ivanić Grad | Sportski Park Zelenjak | 2,000 | |
| Novalja | Novalja | Cissa Strasko | 2,000 | |
| Pomorac | Kostrena | Stadion Žuknica | 3,500 | |
| Segesta | Sisak | Gradski stadion Sisak | 8,000 | |
| Solin Građa | Solin | Stadion pokraj Jadra | 4,000 | |
| Šibenik | Šibenik | Stadion Šubićevac | 8,000 | |
| Zadar | Zadar | Stadion Stanovi | 5,860 |
Belišće did not get a first level license so the promotion playoff against Šibenik was cancelled and Šibenik was automatically promoted.[1]