The 19 year-old is one of Australia's brightest talents and it was reported that Cottagers boss Martin Jol wanted to sign him in the January transfer window.
However, Antonis has no intention of leaving Sydney any time soon and is delighted to have agreed a new two-year deal.
"I'm excited about signing again at Sydney FC," he told the Brisbane Times.
"I started at the club when I was 16 and they have been very good to me. I want to continue my development in Australia before I think about any options overseas.
"I want to concentrate on my club football with Sydney FC and I'm happy this is sorted out so I can concentrate on the game against Newcastle and the rest of the season."
Antonis, who has three international caps to his name, will remain at Moore Park until the end of the 2014-2015 season.