Police are appealing for help to find those responsible for damaging vehicles in Fratton and Cosham.
Officers are linking at least 19 reports of vandalism where bricks have been thrown through the windows of vehicles - we're told no-one has been injured though.
Police say it doesn't look like any items have been stolen from inside vehicles so far - the damage occurred late at night or early in the morning between February 19 and March 13 2013.
Vehicles parked in Queens Road, Carnarvon Road, Kirby Road, North End Avenue, Inhurst Road and Chichester Road in Portsmouth are among those that have been targeted.
Anyone with information is asked to contact police on the 101 number or Crimestoppers on 0800 555 111.