The campaign includes posters that will be placed in bus shelters and on billboards throughout the city.
Law enforcement officials say it's critical that the community not judge these children as criminals or prostitutes, but see them as victims of crime.
"Holding judgment against those children as if they're committing the crime is what allows some societies to make them invisible," District Attorney Nancy O'Malley said. "And when they make children invisible, they don't have to do anything about it."
The message says buying a teenager for sex is child abuse and to ignore that is negligent.
Authorities also hope children being prostituted will see the messages, and discover there is a way out.