Vehicle number plates have been targeted in thefts in Broadbridge Heath, Southwater and Warnham, according to reports received by Horsham police.
Police have urged anyone who has had their number plate stolen to report it by calling 101, and have issued security advice.
A spokesperson said: “Fit theft-proof screws or special number plates to your vehicle.
“Clutch head screws are specially-designed to be virtually impossible to remove once they’ve been fitted. They are very cheap to buy and easy to fit.
“You can buy special number plates which are specifically designed to break apart if they are forcibly removed from your vehicle.”