The pickup was stopped at a checkpoint in Aranyaprathet district.
Police spotted the pickup and signalled it to stop but the driver sped past. Police gave chase and radioed other units to block the road.
The pickup driver was identified as Amporn Sarnnariang, 38, from Sing Buri.
Police found seven Cambodians inside the pickup and five others on the back. They were seven women and five men.
They said they had paid Bt2,500 each to a Cambodia broker to help smuggle to them to work in Bangkok. Amporn was hired to drive them from Sa Kaew’s border to the capital, they said.