Maricopa County Sheriff Joe Arpaio tells KTVK-TV he has the authority to mobilize private citizens to fight crime but hasn't talked to specific districts.
He says he doesn't plan to put posse members inside schools but will have them posted around the perimeters.
Arpaio is known as one of the nation's most high-profile supporters of strict U.S.-Mexico border policy.
His plan announced Thursday comes after two other Arizona officials released ideas for boosting school security.
Attorney General Tom Horne proposed firearms training for one person in each school. And Pinal County Sheriff Paul Babeu proposed training multiple educators per school to carry guns.