The first people have been charged with showing support for Palestine Action after the group was recently banned as a terrorist organisation, the Crown Prosecution Service has said.
Two women and a man were arrested in Westminster after a protest in central London on 5 July.
Jeremy Shippam, 71, of West Sussex, Judit Murray, also 71, of Surrey, and Fiona Maclean, 53, of Hackney, north-east London, were charged with showing support for a proscribed organisation under section 13 of the Terrorism Act 2000.
They are due to appear at Westminster magistrates court on 16 September.
The charges come in advance of a planned protest in support of the group on Saturday afternoon in Parliament Square, central London, with organisers expecting more than 500 people to attend.
