The driver has been taken into custody, police said in a post on social media platform X, Reuters reported.
The incident happened shortly after 8 p.m. (0300 GMT) near East 41st Avenue and Fraser Street, where the Lapu Lapu Day Block Party was taking place.
Canadian Prime Minister Mark Carney said on X: "I am devastated to hear about the horrific events at the Lapu Lapu festival in Vancouver earlier this evening."
Vancouver's Mayor Ken Sim and British Columbia Premier David Eby posted similiar comments on X.
One witness told CTV News he saw a black vehicle driving erratically in the area of the festival just before the crowd was struck.
The Vancouver Sun said thousands of people had been in the area.
“I didn’t get to see the driver, all I heard was an engine rev," Yoseb Vardeh, co-owner of food truck Bao Buns, said in an interview with Postmedia.
“I got outside my food truck, I looked down the road and there’s just bodies everywhere,” said Vardeh, as his voice broke. “He went through the whole block, he went straight down the middle.