Eleven students were going home from schools in Grande Prairie and Beaverlodge when the crash happened Tuesday at a rural intersection.
School officials said one boy was in critical condition following surgery in the Grande Prairie hospital, but was expected to survive.
Two children were airlifted to an Edmonton hospital and were in stable condition.
About seven others, with injuries ranging from cuts to broken bones, went to area hospitals.
The boy in critical condition, a Grade 4 student from the Beaverlodge area, suffered a punctured lung, lacerated liver and broken leg, said Karl Germann, superintendent of Grande Prairie and District Catholic Schools.
"He'll be fine. He talked to us last night, both myself and the principal, and said he'll be back in two to three weeks and not to worry," Germann said.
The bus driver and truck driver were not seriously hurt.
Germann said the injuries could have been a lot worse. "They're lucky they were all on a school bus."
He said the bus was T-boned by an oilfield tanker truck carrying a wide load. The students were tossed around but, because the bus is built like a tank, it wasn't crushed.
RCMP continue to investigate the cause of the crash but said it appears the truck was travelling north on Highway 723 and had the right of way. The bus was going east on Township Road 722 and would have had a stop sign.
Germann said there's a dip in the highway just before the intersection and it's probable the truck was out of sight for a moment before the crash.
Cpl. Roy Kennedy had two nieces and a nephew on board the bus.
"This one kind of hit close to home ... They did get pretty banged up and had to receive some stitches.
"I think it was a pretty scary event for the children on the bus."
Sheldon Rowe, superintendent of the Peace Wapiti Public School Division, said the students on the bus ranged in ages and went to four different schools in the area. Some had been released from hospital by Wednesday afternoon.
He said the bus driver is a caring and capable woman, with years of experience behind the wheel, and she is quite upset about the crash.
"We certainly appreciate the number of parents who inquired as to how she was doing. They know her as a friend and someone who looks after their children."
Note to readers: This is a corrected story. An earlier version said there were 12 students on the bus.
Also on HuffPost