"I believe now is the right time to move on to the next chapter in my life and career," the former England international said in a statement released on Wednesday.
"I feel incredibly honoured and proud to have enjoyed the career that I have and I've loved every moment of it."
Starting his career at Charlton Athletic, Parker went on to play for Chelsea, Newcastle, West Ham and Tottenham before he joined Fulham, his final club, in 2013.
However, as news of his retirement spread across social media, it soon became clear that many mistakenly believed his playing days had come to an end long ago...
https://twitter.com/leroy1305/status/880072589976186880
https://twitter.com/BartHobson/status/880101513691103233
https://twitter.com/SonnyGarner/status/880074301147299840
https://twitter.com/Jaydogg_3001/status/880060912836554753
https://twitter.com/MainManMoni/status/880107150009397249
https://twitter.com/crandall87/status/880081358747344896
https://twitter.com/BubbyWHU/status/880071493312446469
https://twitter.com/hatembomb/status/880065256826994688
https://twitter.com/LosDaGooner/status/880073993952391168
In total, Parker made 450 league appearances. He also represented his country 18 times in an international career that spanned a decade between 2003 and 2013.
Despite holding talks with Fulham about extending his career at Craven Cottage, the decision to end his career comes with his contract due to expire on June 30.