The midfielder, who was most recently with Everton in the Premier League, first made his name with Aston Villa and also enjoyed spells with Stuttgart, Lazio, West Ham and Wolfsburg.
He was capped 52 times by his country and made appearances at both the UEFA European Championships and FIFA World Cup.
Hitzlsperger, who won the Bundesliga title in 2006 with Stuttgart, revealed his decision to quit in an interview with Suddeutsche Zeitung.
"For a few days I am sure I am not playing anymore," he said.
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