Thai voters approved a new junta-backed Constitution that would pave the way for an election next year and give the military, which seized power in a coup two years ago, the final say on future elected governments.
Thai voters cast ballots for the first time since the military toppled the government, choosing whether to approve or reject a junta-backed Constitution.
Thailand's Election Commission said that with 91 per cent of the votes counted, 61 per cent have voted in favour.
The draft won approval in all regions, except the Northeast, which is the stronghold of former premier Thaksin Shinawatra.
The new charter could pave the way for polls next year.
The military has said the new Constitution would stem endemic political corruption and bring stability, but critics have said it will entrench military control.
Campaigning against the draft had been banned and dozens have been detained. Thailand's biggest political parties rejected the Constitution.
After casting his ballot at a polling station in Bangkok, Prime Minister Prayuth Chan-o-Cha said: "Come out (to vote) because today is important for the future of the country.
"This is your duty and this is part of democracy, of an internationally-recognised process."
After the 'yes' vote, the draft will become the Constitution, enhancing the military government's legitimacy in the run-up to an election which Prime Minister Prayuth has promised will happen next year.
The military junta which took power after a coup in 2014 called for the Constitution to be rewritten to ensure "clean politics" in the country.