1998–99 KNVB Cup
The 1998–99 KNVB Cup was the 81st edition of the Dutch national football annual knockout tournament for the KNVB Cup. 61 teams contested, beginning on 11 August 1998 and ending at the final on 13 May 1999.
Ajax successfully defended its 1998 title and successfully pursued its 14th KNVB Cup on 13 May 1999 in De Kuip, Rotterdam, defeating Fortuna Sittard, 2–0. 25,000 attended.
The Cup Winners' Cup tournament no longer existed, Ajax contested the UEFA Cup.
Teams
- All 18 participants of the 1998–99 Eredivisie, six of which entering in the knock-out stage
- All 18 participants of the 1998–99 Eerste Divisie
- 23 teams from lower leagues
- Two youth teams
Group stage
The matches of the group stage were played between 11 August and 2 September 1998. 55 clubs participated, 26 advanced to the next round.| Team | Pts |
| 1. FC Den Bosch 1 | 10 |
| 2. RKC Waalwijk E | 7 |
| 3. VV Katwijk A | 7 |
| 4. SC Feyenoord A | 3 |
| 5. WSC A | 0 |
| Team | Pts |
| 1. AZ E | 9 |
| 2. Veendam 1 | 8 |
| 3. HFC Haarlem 1 | 7 |
| 4. FC Lisse A | 2 |
| 5. Stormvogels A | 1 |
E Eredivisie; 1 Eerste Divisie; A Amateur teams
Knock-out Stage
First round
The matches of the first round were played on October 27, 28 and 29, 1998. The six highest ranked Eredivisie teams from last season entered the tournament this round.E six Eredivisie entrants
Round of 16
The matches of the round of 16 were played on February 2, 3 and 4, 1999.Quarter finals
The quarter finals were played on March 9 and 10, 1999.Semi-finals
The semi-finals were played on April 13 and 14, 1999.Final
The final was played on May 13, 1999.The Cup Winners' Cup tournament no longer existed, Ajax would now play in the UEFA Cup.