Trailblazing Milos Raonic retires from tennis
The big-serving 35-year-old, the first Canadian man to reach a Grand Slam singles final, has not competed in over a year.
He has long been plagued by injuries and said on social media it was time to call it quits.
"This is a moment you know will come one day, but somehow you never feel ready for it," he said.
"This is as ready as I will ever be. I have been the luckiest person to get to live out and fulfil my dreams."
Raonic's best season was in 2016, when he reached the Wimbledon final after defeating Roger Federer in the semis, losing to Andy Murray in the decider.
He also advanced to the Australian Open semi-finals and the ATP Finals the same year, finishing the season as world number three.
He last competed at the 2024 Olympics in Paris.