A zero-tolerance policy in schools is a policy of strict enforcement of school rules against behaviors or the possession of items deemed undesirable. In schools, common zero-tolerance policies concern physical altercations, as well as the possession or use of illicit drugs or weapons. Students, and sometimes staff, parents, and other visitors, who possess a banned item for any reason are always punished. Public criticism against such policies has arisen because of the punishments the schools mete out when students break the rules in ignorance, by accident, or under extenuating circumstances. The policies have also been criticized for their connection to educational inequality in the United States.

School discipline relates to actions taken by teachers or school organizations toward students when their behavior disrupts the ongoing educational activity or breaks a rule created by the school. Discipline can guide the children's behavior or set limits to help them learn to take better care of themselves, other people and the world around them.