The incident occurred last night on Agra-Bombay Road when the trio tried to loot the truck by jumping onto the vehicle and cutting the rope used to fasten goods to it, Sarangpur police station Inspector Sunil Sharma said.
The miscreants, who were chasing the truck on a motorcycle, lost their balance and came under the vehicle, killing them on the spot, he said.
The deceased persons were identified as Rambagas, Laxminarayan and Manoj, he said, adding all the accused were adults.