According to unofficial results announced by state media, Recep Tayyip Erdogan won 52.5 percent of the votes in the race to become the country's first executive president with significantly increased powers.
Electoral officials declared Erdogan the victor of the presidential election.
Erdogan's main rival, Muharrem Ince of the Republican People's Party (CHP), conceded defeat but branded the elections unjust and said the presidential system that now takes effect was "very dangerous" because it would lead to one-man rule.
In his victory speech on Sunday, Erdogan said Turkey's democracy was "an example for the rest of the world".
Celebrations erupted outside Erdogan's residence in Istanbul and AKP headquarters in Ankara, with crowds of flag-waving supporters, AFP correspondents said.
"The restrictions we have seen on fundamental freedoms have had an impact on these elections".
Interested in Turkey? Add Turkey as an interest to stay up to date on the latest Turkey news, video, and analysis from ABC News. "(Turkey) has transitioned to a one-man regime in the fullest sense".
Erdogan, who has been in power for more than 15 years, has repeatedly stressed the necessity of having a powerful executive presidency to create a confident and stable country that will take "steps for the future in a stronger manner".
What do the new powers mean?It won 23 percent in the new parliament and the pro-Kurdish HDP almost 12 percent, above the 10 percent threshold needed to win seats.
In Germany, Sevim Dagdelen, chairwoman of the German-Turkish parliamentary group and an ethnic Kurd, told the dpa news agency that the elections were "neither free nor fair".
Global observers criticized the election Monday, saying it took place on "uneven playing field" tilted in favour of Erdogan and his ruling party, which "enjoyed undue advantage, including in media". Under a new constitution agreed in an April 2017 referendum strongly backed by Erdogan the President can exclusively take a decision without even a prime minister's approval.
Nationalist politician Meral Aksener, tipped for a breakthrough after founding her new Iyi (Good) Party, suffered a disappointing night coming in fourth with 7.3%.
OSCE observer Olivier Henry, left, and Rita Bellens work at a polling station at a primary school in Ankara, Turkey, Sunday, June 24, 2018.
After being declared the victor, Erdogan on June 25 said he would act more decisively against terrorist organizations and would liberate more territory in Syria to allow "our guests" to go home safely, referring to the thousands of Syrian refugees who have fled the bloody seven-year civil war in the Middle East country. The new presidency means that he will have nearly no checks and balances imposed on him, though he will remain dependent on his collaboration with the MHP in parliament.
Hamas's political chief Ismail Haniyeh and Palestinian Authority President Mahmoud Abbas were among the first to call Turkish President Recep Tayyip Erdoğan.
Burcu, a 29-year-old shopkeeper in Istanbul who declined to provide his last name, told ABC News he voted for Ince and is suspicious of the official results.
Erdoğan will assume vast new powers narrowly approved in a referendum a year ago, including the power to appoint senior judges and unelected vice presidents, and to pass decrees with the force of law.
National Alliance parliamentary candidates had vowed that if they secured majority control of the legislature, they would try to roll back the Erdogan-backed constitutional amendments narrowly approved in the 2017 referendum.
He said: "Mr Erdogan is now an all-powerful man, not just de facto but also formally".
Turkey's European Union accession bid stalled some time ago amid disputes on a range of issues, including Ankara's human rights record, especially since the post-coup crackdown.
The EU has on many occasions criticized Turkey, and Erdogan, for a massive crackdown on dozens of thousands of people following a failed military coup attempt in July 2016. Look at the popularity of United States President Donald Trump, Russian President Vladimir Putin, Chinese President Xi Jinping and French President Emmanuel Macron.