It was not the resounding victory President Recep Tayyip Erdogan wanted, but it was a win nonetheless.
Results indicate 51 per cent of the referendum voted "yes" to a constitutional change of the parliamentary system, which would be well short of the 60 per cent he was hoping for.
President Erdogan says unofficial results show around 25 million "yes" votes, 1.3 million ahead of the "no" votes.
Prime Minister Binali Yildirim, a supporter, has praised the high turnout of voters.
"I am grateful to everyone who made the effort to go to the ballot box and cast their ballot. I am grateful to you all, in the name of democracy ... I want everyone to be certain that the result of this referendum will be used to the benefit of everyone. Thank you, Turkey."
President Erdogan's supporters say replacing the parliamentary system with an executive presidency will modernise the country.
The opposition says it fears the changes will make the president too powerful.
It is claiming massive irregularities in the voting, saying the state news agency manipulated the results.
But Mr Yildirim says Turkey has spoken.
"Our nation has made a decision. They've made a choice. And they have approved the presidential government system in this country. No historian, no-one, can stand in front of that. And the nation has shown that they will not bow to any outside forces."
Under the changes, President Erdogan will be head of government as well as head of state and will be given sweeping powers.
Those include the ability to enact laws by decree and to dismiss parliament.
President Erdogan says he is pleased such a big decision has been made peacefully and democratically.
"Prior to this, such significant decisions have been taken either at the end of the independence war, or similar events, or as a result of military coups. Today, we are changing our system of governance in a civil, democratic referendum. That is very significant."
President Erdogan says he expects other countries to accept and support the referendum results.
"We expect other countries and institutions to respect this outcome. Especially those countries we consider to be our allies are expected to support us, be alongside us, especially in our fight against terrorism."
The aftermath of the referendum has not been without difficulty.
Scuffles broke out between "yes" and "no" supporters in Ankara.
A Turkish-based analyst for Stockholm's Institute for Security and Development Policy, Gareth Jenkins, says Turkey is a country divided and lacking trust.
"There's so little trust between the people who oppose Erdogan and Erdogan himself. And we have a highly politicised judicial system now in Turkey as well, so, even if the courts rule that there were no irregularities, a lot of people in the country won't believe it. And this is, again, a very major problem going forward. You really need the people in the country to trust the system."
