"This is a historic decision," Erdogan said after unofficial results confirmed his victory. "This is the most important administrative reform in our history."
The amendments eliminate the office of prime minister and empowers the president with executive authority, including powers to single-handedly issue government decrees.
Erdogan's critics say the vote will create an all-too powerful office for the president. They say Turkey would drift into a one-man rule and further authoritarianism under new powers for Erdogan, an Islamist-populist leader.
Unless Erdogan calls for snap polls Turks are scheduled to go to ballot boxes to elect the president and members of parliament in November 2019.
Prime Minister Binali Yildirim, an Erdogan confidant who campaigned for 'Yes' said elections would be held on time.
Political observers say Erdogan and Yildirim may consider a cabinet reshuffle.
Erdogan became Turkey's first directly elected president in August 2014 when he won 51.5 percent of the nationwide vote.
This is a developing story. Check back to Defense News for more on the vote and its affect on the defense industry.
Burak Ege Bekdil is the Turkey correspondent for Defense News.