The Bees held successful talks with the Dutchman last week and he will take charge at Griffin Park, replacing Mark Warburton as head coach.
The club will also announce his assistant head coach, believed to be Roy Hendriksen, for the 2015/16 season and this will complete Matthew Benham's restructuring of the club.
Warburton and assistant David Weir left the club at the conclusion of their contracts, while sporting director Frank McParland was put on gardening leave.
The former Liverpool supremo was replaced by co-directors of football Rasmus Ankersen and Phil Giles.
Brentford have made one addition to their squad already this off-season with Akaki Gogia signing on a free transfer.