Residents who do not wish to have children calling at their homes on Halloween are being urged to display a sign in their windows.
West Mercia Police said some people living across the force area often felt intimidated by trick or treaters calling at their homes.
The "No trick or treat" signs are available at libraries, community centres and local police stations.
Children are also warned not to go out alone or to enter stranger's houses.
Pc Robin White said: "Police don't want to be spoilsports at Halloween but we are appealing to youngsters to stay safe and be sensible.
"It can be worrying for a resident, especially someone living alone, to have unexpected visitors knocking on the door after dark and demanding money or treats."