Brabants will join the British Canoeing coaching set up as podium technical coach from January 2018, stepping down from his role as the organisation's chief medical officer.
The 40-year-old won gold in the men's sprint kayak in Beijing, becoming the first Briton to win an Olympic gold in a kayak.
He also had two Olympic bronzes, one world gold and three world silvers in a trophy cabinet brimming with silverware.
"I'm really excited to have the opportunity to work as part of a team of world class, experienced coaches and with highly motivated and talented athletes," said Brabants.
"I competed internationally for 20 years and now have the chance to use that experience to help develop our current athletes to compete to the highest level.
"I'm particularly looking forward to working with [canoe sprint head coach] Rene Olsen and learning from his experience taking athletes to Olympic and world championship success."
James Train has also been promoted to women's podium canoe coach, supporting the senior side on their path to Tokyo 2020.
Olsen added: "I am delighted to announce the appointments of Tim Brabants and James Train to join the senior coaching team for our world class canoe sprint programme.
"Tim's experience in high performance sport environments will be incredibly valuable in the development of our athletes. I feel it shows the strength of our team that we have been able to attract Tim to the role.
"James has over the last year been the driving force for taking our women's canoe programme to a world class level. I'm looking forward to working closer together with him in our senior Olympic coaching team.
"I am confident that with these appointments we will strengthen the support we can provide to our athletes and put the programme in a stronger position for year two of our Tokyo mission."