| 1998–99 Slovenian Basketball League | |
| League: | Slovenian Basketball League |
| Sport: | Basketball |
| Season: | Regular season |
| Season Champs: | Union Olimpija |
| Playoffs: | Playoffs |
| Finals Champ: | Union Olimpija |
| Finals Runner-Up: | Pivovarna Laško |
| Seasonslistnames: | Slovenian Basketball League |
| Prevseason Link: | 1997–98 Slovenian Basketball League |
| Prevseason Year: | 1997–98 |
| Nextseason Link: | 1999–2000 Slovenian Basketball League |
| Nextseason Year: | 1999–2000 |
The 1998–99 Slovenian Basketball League, known as Liga Kolinska for sponsorship reasons, was the eighth season of the Premier A Slovenian Basketball League, the highest professional basketball league in Slovenia.
| Pos | Team | P | W | L | F | A | Pts |
| 1 | Union Olimpija | 32 | 29 | 3 | 2738 | 2060 | 61 |
| 2 | Pivovarna Laško | 32 | 27 | 5 | 2848 | 2317 | 59 |
| 3 | Krka | 32 | 23 | 9 | 2602 | 2343 | 55 |
| 4 | Savinjski Hopsi | 32 | 20 | 12 | 2513 | 2342 | 52 |
| 5 | ZM Lumar Maribor1 | 32 | 13 | 19 | 2508 | 2627 | 45 |
| 6 | Loka kava | 32 | 11 | 22 | 2226 | 2555 | 43 |
| Pos | Team | P | W | L | F | A | Pts |
| 7 | Slovan | 32 | 14 | 18 | 2504 | 2468 | 46 |
| 8 | Postojna | 32 | 13 | 19 | 2296 | 2543 | 45 |
| 9 | Triglav Kranj | 32 | 11 | 21 | 2277 | 2426 | 43 |
| 10 | Kraški zidar | 32 | 11 | 21 | 2271 | 2467 | 43 |
| 11 | Pošta Maribor Branik1 | 32 | 11 | 21 | 2308 | 2573 | 43 |
| 12 | Helios Domžale | 32 | 9 | 23 | 2268 | 2638 | 41 |
P=Matches played, W=Matches won, L=Matches lost, F=Points for, A=Points against, Pts=Points
| Qualified for the Playoff stage | ||
| Withdrew from competition |