1998–99 Croatian Second Football League

The 1998–99 Druga HNL was the 8th season of Druga HNL, the second level league in Croatian football.

The format of the league was changed and the five regional subdivisions which composed the Druga HNL in the 1997–98 season were merged into a single nationwide format for the 1998–99 season. A total of 19 clubs competed in Druga HNL this season, in a double round-robin format.