The former France defender, who took in the likes of Arsenal, Chelsea and Tottenham during his career, has told French TV he has decided to call it a day.
Gallas will on Thursday night give a full interview to Sport Confidential about his decision, but in a quote carried by L'Equipe he said: "It is something that is not easy to announce.
"You think that you can continue, but today I cannot."
Gallas started his career with Caen and then joined Marseille, before he was signed by Chelsea in 2001.
He won two Premier League titles with the Blues under Jose Mourinho but left under a cloud in 2006, going to Arsenal as part of the Ashley Cole transfer the other way.
Upon his leaving Chelsea alleged Gallas had threatened to score own goals in their shirt if they did not let him leave - a claim he strongly denied.
Gallas had four years with Arsenal and was made captain by Arsene Wenger, before joining Tottenham in the summer of 2010.
After three seasons with Spurs he transferred to Australian side Perth Glory, who will go down as his last club.
Gallas won 84 caps for France and played in their 2006 World Cup final loss to Italy - it was his goal which saw off the Republic of Ireland in a play-off for the 2010 World Cup after Thierry Henry's infamous handball.
He was also named in the PFA team of the year twice and retires having made 570 career appearances.
Source : PA