A former assistant at Go Ahead Eagles and Zwolle, Maaskant was named head coach of RBC Roosendaal for the 1999–2000 season.

Maaskant worked in Deventer for seven months, came back to Roosendaal, and then moved on to Willem II in the summer of 2004.

Maaskant was sacked in 2007 and signed a one-year contract with MVV Maastricht for the 2007–08 season with an option to extend it for two more years.

In February 2008, he left MVV and signed for NAC Breda to be the auxiliary coach of Ernie Brandts.

[10] In January 2014, Maaskant signed a one-year contract with the Columbus Crew in the Major League Soccer to be their assistant coach.

On 2 January 2015, it was announced that Maaskant had returned as head coach of Eredivisie side NAC Breda.