Massachusetts Booster Seat Law (2026)

Massachusetts is upgraded to an official-source page because it draws steady visitors and its rule is a single age-or-height line, easy to misread as "age 8 and done."

For 2026 checks, the direct answer is: under 8 unless taller than 57 inches in a child passenger restraint (car seat or booster, chosen by the seat's own limits), then a seat belt until age 13. Mass.gov's own guidance says to keep children rear-facing as long as possible and to move to a booster only once the forward-facing harness is outgrown.

The $25 statutory fine is one of the lowest in the country; Mass.gov notes a free car seat inspection by a certified CPS technician is available statewide.

Most states give parents two or three numbers to track. Massachusetts gives one rule with two triggers: under 8 or 57 inches or shorter needs a restraint; clearing either number on its own does not end the requirement, but reaching 57 inches ends it even before age 8.

Because the statute does not name "booster" specifically, Mass.gov's own guidance fills the gap: keep a child rear-facing as long as possible, move to a forward-facing harness once the rear-facing seat is outgrown, then move to a belt-positioning booster once the harness seat is outgrown, typically around age 4 at the earliest.

A child who is under 8 and under 57 inches is covered by the statute regardless of which specific stage they are in. The manufacturer's instructions for the seat in use, not the statute, decide when to move from harness to booster.

Once a child is no longer required to use a child passenger restraint, Massachusetts law still requires a properly adjusted and fastened seat belt until the child turns 13. A driver can be fined under the same statute (7AA) for a child under 13 who is not properly restrained, restraint or belt.

A separate law, Chapter 90 Section 13A, requires anyone 13 or older to wear a seat belt. Mass.gov describes Massachusetts as a secondary-enforcement state for that adult and teen seat belt law, meaning a driver cannot be stopped for a seat belt violation alone. Mass.gov's page does not extend that secondary-enforcement description to the under-13 child restraint law in 7AA.

Section 7AA does not apply to children riding in a school bus, in a vehicle manufactured before 1966 that was never equipped with safety belts, or when a physician has certified that the child is physically unable to use a restraint.

The statute also says a violation is not to be used as evidence of contributory negligence in a civil action, which matters for insurance and injury claims but does not change the restraint requirement itself.

Massachusetts General Laws Chapter 90, Section 7AA sets a fine of not more than $25 for a violation. A separate law, Chapter 90 Section 13A, requires passengers 13 and older to wear a seat belt and is enforced as secondary; Mass.gov does not state that the child restraint law is secondary enforcement.

The $25 statutory maximum is one of the lowest child-restraint fines in the country. Mass.gov also points families to free car seat inspections by a certified Child Passenger Safety technician, which is a more useful resource than the fine amount for most parents.

No. M.G.L. c.90 7AA sets restraint requirements for passengers under 13, and the 57-inch figure is an exit threshold for children, not a rule for adults. A viral notice claiming Massachusetts requires adults under a certain height to use booster seats is not this law; see the adult booster seat law fact check. Searches using the phrase "adult booster seat" usually mean the point when a child can move from a booster to the adult seat belt.

Not sure which type fits your child? Use the seat finder — enter age, height, and weight to see the stage and a matching seat.