Lefteris "Terry" Antonis (Greek: Λευτέρης "Τέρι" Αντώνης; born 26 November 1993) is an Australian soccer player who plays as a midfielder.

Born in Sydney, Antonis played youth football at the Australian Institute of Sport before making his professional debut for Sydney FC at sixteen years of age.

Antonis has played for Australia on three occasions and was a member of the squad which won the 2015 AFC Asian Cup. He previously represented Australia frequently at youth level, including at the 2011 FIFA U-20 World Cup.

A versatile player, Antonis can play as a box-to-box, holding or attacking midfielder, though he is best deployed in deeper roles, where he can create play with his extensive passing range.

Antonis was born in the suburb of Bankstown, Sydney, and is of Greek descent. His brother George Antonis is also a professional soccer player.

He first received media attention in Australia at the age of 10 by winning a football talent competition on the Channel 7 television show Today Tonight, which resulted in a trip to Madrid to make a training skills DVD with David Beckham. Frank Farina, former Socceroos coach and judge of the Channel 7 competition said: "His juggling is very good, he pulled out a squash ball and started juggling that and didn't drop it once, he is very impressive." He also obtained a sponsorship from Adidas because of his exceptional juggling skills.

Former Australian international Alex Tobin described him as "one of the most outstanding young players that I have seen" and "of immense talent without a doubt." He has also been touted as natural successor to Tim Cahill and Brett Holman in the Australian national team.

Antonis holds both an Australian and Greek passport.