| Competition: | Slovenian Third League |
| Season: | 2012–13 |
| Matches: | 338 |
| Total Goals: | 1108 |
| League Topscorer: | Damir Čontala (23 goals) |
| Prevseason: | 2011–12 |
| Nextseason: | 2013–14 |
The season began in August 2012 and ended in June 2013.
| Club | Location | Stadium | 2011–12 position | |
|---|---|---|---|---|
| Beltinci | Beltinci | Beltinci Sports Park | 1st, Pomurska | |
| Bistrica | Slovenska Bistrica Sports Park | 13th | ||
| Čarda | Martjanci | ŠRC Martjanci | 4th | |
| Dravograd | Dravograd | Dravograd Sports Centre | 2nd | |
| Grad | Grad | Igrišče Pod gradom | 10th | |
| Kovinar Štore | Štore | Na Lipi Stadium | 8th | |
| Ljutomer | Ljutomer | Ljutomer Sports Park | 2nd, Pomurska | |
| Malečnik | Malečnik | Berl Sports Centre | 11th | |
| Rakičan | Rakičan | Grajski Park Stadium | 12th | |
| Odranci | Odranci | ŠRC Odranci | 9th | |
| Šmarje pri Jelšah | Šmarje pri Jelšah | Sports Park | 1st, Styrian | |
| Tromejnik | Kuzma | Kuzma Football Stadium | 6th | |
| Veržej | Veržej | Čistina Stadium | 7th | |
| Zreče | Zreče | Zreče Stadium | 5th |
| Club | Location | Stadium | 2011–12 position | |
|---|---|---|---|---|
| Adria | Miren | Pri Štantu Stadium | 11th | |
| Ankaran Hrvatini | Ankaran | ŠRC Katarina | 2nd | |
| Bilje | Bilje | V Dolinci Stadium | 1st, Littoral (Nova Gorica) | |
| Brda | Dobrovo | Vipolže Stadium | 9th | |
| Ivančna Gorica | Ivančna Gorica | Ivančna Gorica Stadium | 5th | |
| Izola | Izola City Stadium | 7th | ||
| Jadran | Dekani | Dekani Sports Park | 3rd | |
| Kamnik | Kamnik | Stadion Prijateljstva | 10th | |
| Rudar | Trbovlje | Rudar Stadium | 1st, Ljubljana | |
| Tabor | Sežana | Rajko Štolfa Stadium | 2nd, Littoral (Koper)1 | |
| Tolmin | Tolmin | Brajda Sports Park | 4th | |
| Zagorje | Zagorje ob Savi | Zagorje City Stadium | 6th | |
| Zarica | Kranj | Zarica Sports Park | 8th |