Police said the driver ran away after a brief chase, at the Moey City market in Tambon Tha Sailuad in Mae Sot at 1am.
Pitchan Ngernyerm, 37, the owner of the truck, said he was delivering milk to a 7-Eleven on Chidlom Road in Tambon Mae Sot of Mae Sot district when the vehicle was stolen.
He said he left the truck engine running and the keys in the ignition while he made a delivery.