It is believed that Eindhoven will pay Alkmaar a fee in the region of £6m for the 19-year-old midfielder.
The transfer will be made official following a medical on Monday.
"We have been looking at signing him for a long time," PSV's technical director Marcel Brands told the club's official website.
"With him, we have a very talented Dutch player who fits the philosophy of PSV."
Maher, who was born in Morocco but selected to represent the Netherlands, has been capped four times at senior international level.