Mertesacker joins Philipp Lahm and Miroslav Klose, who also retired from international football following Germany's World Cup triumph last month.
The 29-year old has won 104 caps for his country and was part of the Germany squad that became the first European side to lift the World Cup on South American soil.
Mertesacker is one of three German players, along with Mesut Ozil and Lukas Podolski, who have been given an extended break by Arsenal boss Arsene Wenger following their triumph in Brazil.
The towering centre-half will now concentrate on his career with Arsenal, who he joined in August 2011 from Werder Bremen and has played 90 games for the Gunners.
Mertesacker said: "The World Cup in Brazil was a golden conclusion.
"I want to win the league with Arsenal and also take a shot at the Champions League
"Young players are going to come through. There's no reason for us to have any fears. We have a stronger squad now than ever before."
Mertesacker says he will never forget his time with the national team especially the two months spent in Brazil over the summer.
"They were the eight best weeks of our lives," he added.