| Competition: | Croatian First Football League |
| Season: | 1998–99 |
| Winners: | Croatia Zagreb 5th Croatian title 9th domestic title |
| Continentalcup1: | Champions League |
| Continentalcup1 Qualifiers: | Croatia Zagreb Rijeka |
| Continentalcup2: | UEFA Cup |
| Continentalcup2 Qualifiers: | Hajduk Split Osijek |
| Continentalcup3: | Intertoto Cup |
| Continentalcup3 Qualifiers: | Varteks Hrvatski Dragovoljac |
| Best Player: | Miljenko Mumlek |
| League Topscorer: | Joško Popović (21) |
| Biggest Home Win: | Varteks 7–0 Šibenik |
| Biggest Away Win: | Mladost 127 0–4 Croatia Zagreb |
| Highest Scoring: | Zadarkomerc 5–3 Varteks |
| Matches: | 192 |
| Total Goals: | 541 |
| Average Attendance: | 4,158 |
| Prevseason: | 1997–98 |
| Nextseason: | 1999–2000 |
The 1998–99 Croatian First Football League was the eighth season of the Croatian top-level football league since its establishment.
| Team | Manager1 | Location | Stadium | Capacity | |
|---|---|---|---|---|---|
| Cibalia | Srećko Lušić | Vinkovci | Stadion HNK Cibalia | 10,000 | |
| Croatia Zagreb | Ilija Lončarević | Zagreb | Stadion Maksimir | 37,168 | |
| Hajduk Split | Ivan Katalinić | Split | Stadion Poljud | 35,000 | |
| Hrvatski Dragovoljac | Branko Tucak | Zagreb | Stadion NŠC Stjepan Spajić2 | 5,000 | |
| Mladost 127 | Mato Šarić | Suhopolje | Stadion Park | 5,000 | |
| Osijek | Stanko Poklepović | Osijek | Stadion Gradski vrt | 19,500 | |
| Rijeka | Nenad Gračan | Rijeka | Stadion Kantrida | 10,275 | |
| Slaven Belupo | Luka Bonačić | Koprivnica | Gradski stadion u Koprivnici | 4,000 | |
| Šibenik | Stanko Mršić | Šibenik | Stadion Šubićevac | 8,000 | |
| Varteks | Dražen Besek | Varaždin | Stadion Varteks | 10,800 | |
| Josip Bajlo | Stadion Stanovi | 5,860 | |||
| NK Zagreb | Zdenko Jurički | Zagreb | Stadion Kranjčevićeva | 8,850 |
It was contested by 12 teams, and Croatia Zagreb won the championship.In the first stage upper six teams advance to Championship Group, bottom six to Relegation Group, with 50% of points taken to the next phase of the competition.
| Rank | Player | Club | Goals |
|---|---|---|---|
| 1 | Joško Popović | Šibenik | 21 |
| 2 | Zvonimir Deranja | Hajduk Split | 14 |
| Igor Musa | Rijeka | ||
 Barnabás Sztipánovics | Rijeka | ||
| 5 | Nino Bule | NK Zagreb | 13 |
| Miljenko Mumlek | Varteks | ||
| 7 | Stanko Bubalo | Osijek | 10 |
 Mirza Golubica | Mladost 127 | ||
| Veldin Karić | Varteks | ||
| Jakša Krstulović | Zadar | ||
| Edin Mujčin | Croatia Zagreb |