The tour bus that belongs to BRT Travel crashed into a ditch and knocked over a light pole on Chalermphrakeit 9 Rd (Bypass) north bound.
The bus was carrying two tour guides as well 18 Chinese passengers.
The victims were taken to either Bangkok Hospital, Phuket international or Vachira Hospital, while rescue workers had to battle their way in to rescue the remaining victims trapped inside the wreckage.
Police officers at the scene said the bus driver was not injured.
More details to follow.