The school bus was hit by the speeding truck at the sector 25-31 intersection in Noida early on Thursday, police said.
The bus belonged to the Army Public School and was carrying 38 school when the accident took place. Nine students were injured in the accident while the others escaped unhurt, an official said.
Senior Superintendent of Police Preetinder Singh told IANS that two students suffered fractures while others have minor injuries.
The truck driver slipped away after the accident, leaving behind the truck.
A probe, an official said, will also be ordered on how come the school children were going to school when authorities have ordered closure of schools Jan 18 owing to the cold wave.