Turkey has completed a 556-kilometre wall along its border with Syria, the Defence Ministry said on Tuesday on its Twitter feed.
The wall was designed as a security measure and is made of concrete blocks. Photos from the ministry show the tops of the blocks are covered in barbed wire and there are guard towers placed at intervals.
The project was done in cooperation with TOKI, the state-run public housing body. The body said the wall is about three metres high.
The full length of the border is 911 kilometres.
In the first years of the Syrian civil war, fighters, including many who joined jihadist organizations such as Islamic State, were able to cross the porous border into Syria.
Islamic State has since been driven away from the border by a Turkish land operation inside Syria.
Turkey remains concerned by Kurdish authorities who control most of the border on the Syrian side, though these forces work with the United States in the war against Islamic State.
Human rights groups have expressed concerns that Turkey's increased security on the border prevents refugees from fleeing Syria. There have been reports of Syrians being shot while trying to flee the war-torn country.
Turkey hosts more than 2 million Syrian refugees and hundreds of thousands from Iraq and other countries.