ESPN's Adrian Wojnarowski reports the contract is for $72 million over four years and includes a player option for the 2024-25 season.
The contract will begin in the 2021-22 season, as Anunoby still has one year remaining on his rookie deal. The deadline for Anunoby to sign his extension was Monday at 6 p.m. ET, or else he would have become a restricted free agent next off-season.
"OG is the epitome of the skilled, powerful, determined player we want in our organization long-term. Remember, he doesn't shoot to miss," Raptors general manager Bobby Webster said in a statement. "We're really pleased OG will be with us for seasons to come."
The Raptors selected Anunoby 23rd overall in 2017 and he hit the ground running the following season, starting 62 of 74 games as a 20-year-old rookie. A versatile six-foot-eight forward, Anunoby has played every position but point guard in his three-year Raptors career, adding shooting guard to his resume this past season.
The 23-year-old posted new career highs in points (10.6), rebounds (5.3), assists (1.6) and steals (1.4) per game last season, while improving his shooting volume and success rate.
He cemented himself in Raptors lore this summer when he hit a last-second buzzer-beater to defeat the Boston Celtics in Game 3 of the Eastern Conference semifinals.
Anunoby's new contract now locks in the final piece of the next generation of Raptors stars long term after forward Pascal Siakam signed a four-year, $130 million extension last summer and guard Fred VanVleet signed a four-year, $85 million contract in free agency last month. With veteran centres Serge Ibaka and Marc Gasol now plying their trades in Los Angeles, and 34-year-old Kyle Lowry entering the final year of his contract, the Raptors are poised to transition into the next generation seamlessly.