Several tyres were punctured and deflated by vandals along one road in Weedon.
The tyres on the vehicles, which were all parked overnight in Regency Close, were damaged sometime between 5pm on Wednesday, June 24 and 5.50am on Thursday, June 25.
Tyres on seven vehicles appear to have been punctured by a sharp instrument in the side wall.
PC James Shorthouse said: “This was a mindless act of vandalism and I would urge anyone who saw anything suspicious in the area or has any information about who may be involved, to contact police as soon as possible.
“Fortunately, on this occasion, the vehicle owners noticed the damage to their tyres, but it can be difficult to spot and could potentially put drivers, passengers and other road users at serious risk.”
Witnesses, or anyone with any information, are asked to call Northamptonshire Police on 101.
Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111 or use the anonymous online form at www.crimestoppers-uk.org.