The 29-year-old won 104 caps for his country and was a late substitute in Germany's 1-0 FIFA World Cup final victory over Argentina last month.
The centre-back becomes the third Germany player to retire following their triumph in Brazil, joining veteran striker Miroslav Klose and former captain Philipp Lahm.
"First and foremost it was about me, after a 10-year career in the team, being able to say when the chapter ended," Mertesacker told Suddeutsche Zeitung newspaper.
Mertesacker also cited a desire to focus on his club football with Arsenal as a reason behind his decision.
He scored four goals for Germany in his career and was also a member of the squad that lost the UEFA Euro 2008 final.
