Mustakim Jaman, 23, of Hudson Road, Southsea, has been charged under section five of the Terrorism Act 2006.
He is the brother of Ifthekar Jaman, who was killed in Syria in December.
Mr Jaman is due at Westminster Magistrates' Court on Monday. Another brother, Tuhin Shahensha, 26, has also been charged with terrorism offences.
Mr Shahensha, also of Hudson Road, appeared in court on Friday accused of planning to fight in Syria. He is due to appear at the Old Bailey on 14 November.
The two men, of Hudson Road, Southsea, were arrested along with a number of other people in Hampshire and London on 14 October by the South East Counter Terrorism Unit (SECTU).
A 57-year-old man and a 48-year-old woman have been released on bail.
A 23-year-old woman from Farnborough and a 29-year-old woman from Greenwich, south-east London, have been released without charge.

Three people were stabbed when thousands gathered for a water fight in the park which descended into violence last week.
The 18-year-old man was arrested earlier and remains in custody.
Another man, 18, and a 17-year-old boy, have also been arrested in relation to disorder in McDonald's in Marble Arch.
Eleven people have now been arrested after the events on Tuesday 19 July.
The arrests came after police released a gallery of photos of suspects linked to the disorder that saw three people, including a police officer, stabbed.
A second officer suffered injuries from a flying bottle as officers tried to contain aggressive crowds that had gathered.

The singer is talking and "expected to make a full recovery", her lawyer said.
Rebecca J Thyne said she had visited Mitchell on 26 June, and the singer was "happy to be home".
The comments came in papers relating to Mitchell's conservatorship, and follow reports last month that the Big Yellow Taxi singer was unable to speak.
David Crosby - who dated Mitchell in 1967 - told The Huffington Post the star faced a long "struggle" after  being found unconscious in her home on 31 March.
"She took a terrible hit," he said. "She had an aneurysm, and nobody found her for a while. And she's going to have to struggle back from it the way you struggle back from a traumatic brain injury.
"To my knowledge, she is not speaking yet."
But Mitchell's lawyer has painted a more optimistic picture.
"When I arrived she was seated at her kitchen table feeding herself lunch," Thyne wrote.
"She also told me that she receives excellent care from caregivers round-the-clock. It was clear that she was happy to be home and that she has made remarkable progress.
"She has physical therapy each day and is expected to make a full recovery."
The court filing recommended that Mitchell's longtime friend Leslie Morris, who has been acting as her temporary conservator, be officially appointed her conservator.
According to Thyne, Mitchell should be judged to lack the capacity to give informed consent for medical treatment.
The brother of a Portsmouth man killed while fighting for Islamic State (IS) in Syria has been charged with preparing terrorist acts.
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A man has been arrested on suspicion of attempted murder after a stabbing during a night of disorder in London's Hyde Park.
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Joni Mitchell has made "remarkable progress" since she suffering a stroke and brain aneurysm in March, according to court documents.