Several students were on the bus when it hit the child early Friday in St. Albert, a bedroom community north of Edmonton.
The boy had been walking with other children to Ecole Marie Poburan, a French immersion Catholic elementary school, said Const. M.J. Burroughs. The boy was crossing a road across from the school and the bus was turning right, she said.
The road has a crosswalk but no lights. There is a pedestrian crossing with lights at the next corner.
It wasn't immediately known if school crossing guards had been posted there, said David Keohane, superintendent of Greater St. Albert Catholic Schools.
The name of the boy wasn't released.
Cindy de Bruijn said her son is in the same Grade 2 class as the dead boy and she often talked with his mother and other parents about the "ridiculously busy" intersection.
Speeders aren't the problem, she said. It's mostly drivers making turns.
"They're nipping at your heels or trying to beat you through the intersection," she told reporters outside the school. "My daughter in Grade 8 comes home once a week and says, 'Oh, I had my tail nipped off today,' by cars skimming right by her because they're desperate to get through."
De Bruijn said it was only a matter of time before a student was hit.
"It could have been anybody on any day because time after time, vehicle after vehicle, this same thing happens."
St. Albert Mayor Nolan Crouse quickly ordered a review of all crosswalks and intersections at the 25 schools in the city.
"I'm jumping ahead because I don't know what the investigation is going to show. But we have an obligation as a community to make sure there's no stone unturned."
RCMP said students on the bus who witnessed the accident were escorted into the nearby school for counselling. They had been on their way to two different public schools in the area.
A support team was also at the Marie Poburan school throughout the day to help its 450 students.
The bus involved was operated by First Student Canada. Barry Wowk, superintendent of the St. Albert Public School District, said he didn't know any details about the driver.
RCMP investigators don't believe the driver had been drinking, said Burroughs. She said officers were interviewing witnesses, and traffic analysts were studying the scene. No charges had been laid.
Alberta Education Minister Jeff Johnson offered his condolences to the child's family.
"The loss of a young life is tragic and, as a father, my heart breaks for the child's parents," he said in a release.
Wowk said prayers also need to go out to the driver.
"Many lives have been changed today but we can hope and pray that our community will come together once again to help each other heal."