Posters telling Halloween trick or treaters they will not be welcome at homes are being distributed by police.
Police want communities to feel safe on 31 October
The Dorset campaign has been introduced after police recorded 200 incidents in 2005 of anti-social behaviour linked to the traditional door-to-door calls.
Ch Insp David Dent, said: "For those living on their own and the elderly it can be quite a distressing time."
He said police did not want to stop "harmless fun" but hoped youngsters would respect those not involved.
Mr Dent added: "There are people who don't want a large number of young people at their home, many of them are vulnerable and elderly.
"Hopefully it will all be harmless fun but it can intimidate some people.
"We want to ensure that communities across Dorset feel safe this Halloween."