A gun was taken from a student at the Laquey school on Monday.
The incident briefly put the school on lockdown at around noon and the Missouri Highway Patrol and Pulaski County deputies responded.
County Sheriff Jimmy Bench says a teacher noticed a boy who was acting strangely and it led to the recovery of a gun that was in his possession.
No injuries occurred and the sheriff says no students or staff members were threatened.
Further details including the name and age of the student have not been made public.