The 1999 Grolsch Open, also known as the Dutch Open, was an ATP men's tennis tournament played on outdoor clay courts in Amsterdam, Netherlands that was part of the World Series of the 1999 ATP Tour. It was the 42nd edition of the tournament and was held from 2 to 8 August. Sixth-seeded Younes El Aynaoui won the singles title.
See main article: 1999 Grolsch Open – Singles. 
Younes El Aynaoui defeated 
Mariano Zabaleta 6–0, 6–3
See main article: 1999 Grolsch Open – Doubles. Sjeng Schalken / Paul Haarhuis defeated 
Devin Bowen / 
Eyal Ran 6–3, 6–2