The tradition on the Oct. 31 holiday is for children in costumes to go door-to-door to receive candy from their neighbors.
For the second straight year, parole and probation agents plan to team with local police to dissuade sex offenders who are not allowed to have contact with children from participating in the holiday.
"We actually print out the signs for the offenders and hand them to them," said Elizabeth Bartholomew, a spokeswoman for the Division of Parole and Probation. "We expect them to post the signs."
The program is based on similar initiatives in other states. Last year, no sex offenders in Maryland violated their parole or probation, Bartholomew said.
The effort is particularly intense in Baltimore, home to more than 200 offenders who are barred from contact with children.
In addition to the signs, all such offenders have been advised in a letter to stay home from 6 p.m. on Halloween until the next morning, leave their lights off and refuse to answer their doors.
Offenders can arrange with their parole or probation officers to be elsewhere that night, and accommodations can be made for offenders who abide by the restrictions but do not want to post the signs, Bartholomew said.
"There will be some houses where it's a sex offender's house and there's not a 'No Candy' sign posted, but in all those instances, someone will be going to the house to make sure the right thing is happening at that house," Bartholomew said.
Several states, including Delaware, New Jersey, Illinois, Virginia and Texas, ban registered sex offenders from handing out candy on Halloween, going to kids' parties, or being on the streets.