Mouloud Tahari is the third person charged in the investigation alongside his mother and former Guantanamo Bay detainee Moazzam Begg.
All three were arrested last week in England's second city of Birmingham.
Tahari spoke only to confirm his name and date of birth when he appeared at a London court.
He was remanded in custody to appear at the Old Bailey central criminal court on March 14 with his mother, Gerrie Tahari, and Begg, who were charged over the weekend.
Begg, who spent three years at the US detention camp in Cuba before being released without charge in 2005, is accused of providing terror training and funding terror abroad.
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No plea was entered at today's hearing. Tahari's lawyer Gareth Peirce said outside court that he denied the charge and would therefore plead not guilty.
A growing number of young people from European countries are facing legal charges over going to fight in Syria, where a civil war is raging involving President Bashar al-Assad's forces, rebels and Islamist fighters.
Britain too has seen a major increase in Syria-related arrests in recent months. Begg is the first former Guantanamo detainee to be arrested in Britain in connection with Syria.
They arrests came after after cash totalling over $75,000 (almost 55,000 euros) in pounds sterling, dollars and euros was seized at the southeastern English port of Dover in December 2012, police said.
"We are working with our partners around the country to ensure money intended to help those in need in Syria is not used for criminal activity or in the terrorist arena," said Detective Chief Superintendent Chris Hogben.