Our overview of student rights at school introduces the basic rule: school searches use reasonable suspicion, a lower bar than the probable cause police need on the street, because schools have a recognized interest in keeping campus safe and orderly. That single rule plays out differently depending on what is actually being searched. A locker, a car in the school lot, and the contents of a phone each raise a different privacy question, and courts have not treated them identically.
The baseline: reasonable suspicion, not probable cause
In New Jersey v. T.L.O., the Supreme Court held that a school search is reasonable when there are reasonable grounds to suspect it will turn up evidence of a rule violation or crime, and when the search itself is not excessively intrusive given the student's age and the reason for the search. This standard applies to school administrators, and courts have generally extended it to a school resource officer acting at the school's direction for an ordinary disciplinary matter — though not to a full criminal investigation, which is covered in our article on SROs and police referrals.
Lockers: usually the school's property to begin with
A school locker is generally owned by the school and only loaned to a student for storage, which most courts treat as meaning the student has a reduced expectation of privacy in it compared to, say, a backpack or pockets. Many districts also state in their handbook that lockers may be searched at any time, sometimes without the individualized suspicion T.L.O. otherwise requires, precisely because the school retains a form of joint access.
Whether a specific locker search needs individualized suspicion or not can depend on exactly what the district's written policy says and what state law provides, so the handbook language is worth checking rather than assuming the strictest or the loosest possible rule applies.
Cars in the school lot sit somewhere in between
A car is personal property in a way a school locker generally is not, so courts have been less willing to treat it as automatically subject to search the way a locker sometimes is. At the same time, many districts condition the privilege of parking on campus on an agreement, often signed as part of getting a parking permit, that allows the car to be searched under the same reasonable-suspicion standard as anything else on campus.
The practical takeaway is that parking on school property is often not privacy-neutral: check what the parking agreement or permit application actually says before assuming a car is treated like a personal, off-campus vehicle.
Phone content is the least settled area
In Riley v. California, the Supreme Court held that police generally need a warrant to search the contents of a cell phone, even when arresting someone, because a modern phone holds an amount and variety of personal information that a pocket or bag never could. Riley was a case about police, not school administrators, so it does not directly control what a principal can do — but courts handling school phone-search cases since then have increasingly cited its reasoning about how much a phone actually reveals when deciding whether a school's search of a phone's contents went further than T.L.O. allows.
In practice, this makes phone content searches the most contested category: a school taking a phone to confirm it exists is different from a school scrolling through messages, photos, or an app's history, and the second is the part courts scrutinize much more closely. If a phone is taken, asking whether its contents were searched, by whom, and under what specific suspicion is a reasonable and important question.
Remember this
- New Jersey v. T.L.O.'s reasonable-suspicion standard is the baseline for school searches, but lockers, cars, and phones don't all get treated the same.
- Lockers are usually school property, so district policy sometimes allows searching them with less individualized suspicion than other places.
- Parking on campus is often conditioned on a signed agreement allowing a car search under the school standard — check the parking agreement.
- Phone content searches draw the most scrutiny, echoing Riley v. California's reasoning about how much a phone actually reveals.
Sources
This article provides general educational information, not individualized legal advice. KidsKnowRights is not a law firm, and reading this article does not create an attorney-client relationship. Laws vary by state, age, and circumstances, and they change over time. For advice about a real situation, talk with a licensed attorney or a legal aid organization.