Anthony Small, 33, was found not guilty of disseminating terrorist publications and supporting a proscribed group.
A trial at the Old Bailey heard accusations that he put boxing gloves items and a championship belt on eBay to raise money to get to Syria.
Mr Small was also cleared of conspiracy to possess false identity documents with improper intention.
He had been arrested after Michael Coe, 34, of Central Park Road in east London, and Simon Keeler, 44 of Solander Gardens in east London, were found with false documents in the back of a lorry at the port of Dover in November last year.
Coe has also been cleared of conspiracy to possess false identity documents with improper intention.
However both Coe and Keeler have already admitted a separate charge of possessing false documents.
They will be sentenced at a later date.
When Coe and Keeler were found with the false documents, Coe told police he was trying to get to Sweden to visit his wife, and Keeler that he was trying to reach his wife in Turkey.
The jury was told Mr Small - who won the British and Commonwealth light middleweight championships in 2009 - was not with the pair as he had broken his hand two days earlier.
Mr Small told the court he had intended to visit his Turkish ex-wife on urgent family business. He insisted he had "never" supported people who encouraged terrorism.
The jury could not agree on a final charge against Mr Small of supporting a terrorist organisation, and the prosecution has until Friday to decide whether to pursue it.
A former boxing champion has been cleared of plotting to travel to Syria to fight with so-called Islamic State.