Sam Dekker scored 12 of his 18 points in the final period to help the Raptors (3-2) erase an eight-point deficit during the final 12 minutes.
Kyle Kuzma hit six of eight 3-pointers he shot and finished with a team-high 24 points in just less than 30 minutes for the Wizards (0-3), who close out their preseason on Friday at New York.
Gary Trent Jr. scored 12 points for Toronto, which played without forward OG Anunobi, forward-center Chris Boucher, wing Yuta Watanabe, forward Pascal Siakam and guard Fred VanVleet. Forward Precious Achiuwa, acquired from Miami in a sign-and-trade that sent star guard Kyle Lowry from the Raptors to the Heat, had nine points and 10 rebounds. Top Toronto draft choice Scottie Barnes had nine points and seven assists.
Washington guard and first-round draft choice Corey Kispert played nearly 17 minutes and scored just two points to go with three assists.