The bus belonged to the Twin Lakes School Corp. in Monticello, according to the Logansport Pharos-Tribune. The driver was the only survivor on the bus and was flown to a hospital in Indianapolis, 70 miles to the south.
The two dump truck drivers were not injured, the newspaper said.
The crash occurred at the intersection of two U.S. highways, said 1st Sgt. Dave Bursten of the Indiana State Police.
"There are multiple fatalities, and it does involve a school bus and schoolchildren aboard the bus," Bursten said.
A dump truck had tried to slow for a turning vehicle but was unable to stop and swerved into the oncoming lane, clipping the school bus, the Pharos-Tribune reported. The bus flipped and slid into oncoming traffic, where another truck struck the roof and pushed the bus into a ditch.
Television video from the crash scene showed the bus upright, its roof crushed.
The collision comes just days after police said a tractor-trailer driver on his cell phone hit a school bus in Florida, killing a 13-year-old girl.
Slideshow archive | ABC13 wireless | Help solve crimes