Barry last played for West Bromwich Albion in the Championship last season, making six appearances in all competition for the Baggies, who have gained promotion to the Premier League.
Barry is the Premier League’s highest all-time appearance maker, with 653 appearances taken in for four clubs in the top flight.
Barry came through the youth ranks at Aston Villa and was club captain by the time he completed a £12m to Manchester City in the summer of 2009.
At Manchester City, Barry helped the Cityzens win the FA Cup in 2011 before adding the Premier League title to his list of laurels a year later.
Barry joined Everton initially on loan in the 2013/2014 season before sealing a permanent switch to Goodison Park the following season.
The tributes have been flowing from some of Barry’s former clubs since making his retirement intentions known.
Aston Villa wrote on Twitter: '441 appearances, 52 goals and more than a decade of service at Villa Park. Wishing Gareth Barry all the best in his retirement, and congratulations on a wonderful career!'
Meanwhile, West Brom wrote: 'An extraordinary, record-breaking career. All the best in retirement, Gareth Barry.'
Having made his England debut in 2000, Barry went on to win 53 caps for the Three Lions, scoring three goals.
