Police Scotland said a man, whose age has not been given, was arrested under the 2000 Terrorism Act.
The development was revealed a day after five people with alleged links to dissident republicanism appeared in court charged with terrorism offences and conspiracy to murder.
Anton Duffy, Martin Hughes and Stacy McAllister, from Glasgow, Paul Sands, from Ayr, and Edward McVeigh, from Portpatrick, Dumfries and Galloway, were arrested last Wednesday in the operation led by Police Scotland and involving the Police Service of Northern Ireland and the security service.
No other details about the latest arrest have been released by Police Scotland.
Duffy, 39, Hughes, 34, Sands, 30, McVeigh, 26, and McAllister, 27, appeared separately in private at Glasgow Sheriff Court yesterday and were charged under Section 5 of the Terrorism Act, which covers the preparation of terrorist acts, and conspiracy to murder.
All five made no plea or declaration and they were remanded in custody.