A solid majority of Turkish voters approved sweeping changes to their military-era constitution - a referendum hailed by the government as a leap towards full democracy in line with its troubled bid to join the European Union.
With 99% of the vote counted, 58% had cast ballots in favour of the constitutional amendments, state-run TRT television said.
About 42% voted "no", heeding opposition claims that the reforms would shackle the independence of the courts.
The referendum on 26 amendments to a constitution crafted after a 1980 military coup became a battleground between the Islamic-oriented government and traditional power elites - including many in the armed forces - who fear Turkey's secular principles are under threat.
Voter turnout was 78%, and the result amounted to a vote of confidence in the ruling Justice and Development Party ahead of elections next year.
"We have crossed a historic threshold toward advanced democracy and the supremacy of law," prime minister Recep Tayyip Erdogan said at his party headquarters in Istanbul.
"The regime of tutelage in Turkey will now come to an end," he said. "The mentality will be so that those enthusiastic for military coups will see their enthusiasms stuck inside them."
The amendments make the military more accountable to civilian courts and allow civil servants to go on strike. The opposition, however, believes a provision that would give parliament more say in appointing judges masks an attempt to control the courts, which have sparred with Mr Erdogan's camp.
The changes would also remove immunity from prosecution for the engineers of the 1980 coup. Kenan Evren, the military chief who seized power and became president, is 93 and ailing. Street clashes marred voting at several polling stations in provinces with large Kurdish populations.
A Kurdish party urged supporters to boycott the ballot, arguing that the proposed changes would not advance the rights of the ethnic minority. Since Saturday, police detained 138 people suspected of threatening people into boycotting the vote or casting their ballot in a certain way, Interior Minister Besir Atalay said.