The Thai spikers powered back from 2-1 down to stun the Caribbean team 3-2 in their final Pool B match, played in Gdansk, Poland.
The Thais took the opening set before falling 2-1 behind to a team ranked six places above them at No 8 in the world.
However, top-scorers Ajcharaporn Kongyot with 26 points and Pimpichaya Kokram (25) led Thailand back from the brink to stun the Dominicans in a thrilling five-setter, 31-29, 16-25, 21-25, 25-22 and 15-11.
With the victory, the Thais rose one place in the world rankings to No 13 while Dominican Republic fell to ninth.
Thailand’s fourth win in Pool B saw them end the group stage in second behind Turkey on points difference.
The Thai spikers guaranteed their qualification for the second round after beating Turkey (3-2), Croatia (3-0), South Korea (3-0) and Dominican Republic, with their only loss in the competition so far coming against Poland (3-0).
In the second round, Thailand will face Canada on Tuesday (October 4), Germany on Wednesday (October 5), Serbia on Friday (October 7) and the US on Saturday (October 8).
All matches will be broadcast live on Workpoint TV (Channel 23) at 8pm, Thai time.