Former Iranian national player will wear No 16 jersey in the Australian club during the move until the end of this season.
Ghoochannejhad has signed a 2-year contract with the Cypriot club ahead of the 2018-19 campaign and managed to score two goals during his 13 appearances in APOEL.
The 31-year-old announced retirement from national in July 2018, after Team Melli manager Carlos Queiroz didn’t use the experienced player in any of the team’s three games at the 2018 Russia World Cup. He scored 17 goals during his 6-year long national career in 44 appearances.
"I'm excited to be joining Sydney FC and looking forward to the challenge of the A-League and AFC Champions League," Ghoochannejhad said, adding, "to be joining Australia's most successful club is a fantastic move for me, and to test myself against the best in Australia and Asia will be an unbelievable experience.”
"Sydney FC's record in recent times is phenomenal and they have some fantastic players … I can't wait to link up with my new team-mates, help them add to their success and bring more trophies to the club."
With 11 weeks remaining, Sydney FC stands third in A-League with 32 points, five points behind the leaders Perth Glory. The team will also vie at 2019 AFC Champions League in group H along Kawasaki Frontale, Shanghai SIPG and a third team which yet to be determined in a playoff.
MAH/4526966/PR