Massachusetts Car Seat Laws (2026): Ages, Belt Rule & $25 Fine

Massachusetts requires a child passenger restraint until age 8, or until a child exceeds 57 inches in height if that happens first, and a seat belt for children under 13, under Mass. Gen. Laws c. 90, §7AA. The maximum fine is $25. This reflects the statute's text as of September 2026.

Jurisdiction scope: This page covers Massachusetts state law only, specifically Mass. Gen. Laws c. 90, §7AA. It does not cover local ordinances.

What Massachusetts requires

Massachusetts law states that a child passenger "under the age of 8 shall be fastened and secured by a child passenger restraint, unless such passenger measures more than 57 inches in height." The statute does not create separate rear-facing, forward-facing, and booster categories the way some states' laws do; it sets one restraint duty by age and height, leaving the specific seat type to the restraint and vehicle manufacturers' own instructions. A child under 13 who is not covered by the restraint duty, either because they have turned 8 or because they exceed 57 inches, "shall wear a safety belt which is properly adjusted and fastened."

Exemptions

Three situations fall outside the restraint and belt duties: a child riding as a passenger in a school bus; a passenger in a motor vehicle made before July 1, 1966 that is not equipped with safety belts; and a child who is "physically unable to use either a conventional child passenger restraint or a child restraint specifically designed for children with special needs," when a physician certifies that condition in writing and states the reasons the standard or special-needs restraints are inappropriate. The statute states that "the provisions of this section shall not apply" to a child covered by that physician-certified condition, so this is a full exemption from the restraint duty itself, not a rule about which type of restraint to use.

Penalty for a Massachusetts car seat violation

The maximum fine is $25. Massachusetts' statute carves out one specific case from that fine: "said twenty-five dollar fine shall not apply to an operator of a motor vehicle licensed as a taxi cab not equipped with a child passenger restraint device." That carve-out removes only the fine for a taxi operator in that situation; it does not exempt a taxi from the underlying restraint duty itself. The statute does not include a waiver or dismissal provision for a driver who later obtains a conforming restraint.

The same section adds two protections beyond the fine amount. A violation "shall not be used as evidence of contributory negligence in any civil action," so it cannot be used against a parent or driver in a lawsuit over a crash. A violation also "shall not be deemed to be a conviction of a moving violation of the motor vehicle laws for the purpose of determining surcharges on motor vehicle premiums" under c. 175, §113B, so it does not by itself raise a driver's insurance premiums the way a moving-violation conviction would.

Unattended children in vehicles

Massachusetts has no law written specifically to address a child left unattended in a vehicle. Massachusetts' general child-endangerment statute, Mass. Gen. Laws c. 265, §13L, could still reach a caregiver whose conduct creates real risk: it punishes "whoever wantonly or recklessly engages in conduct that creates a substantial risk of serious bodily injury or sexual abuse to a child" or "wantonly or recklessly fails to take reasonable steps to alleviate such risk where there is a duty to act," with imprisonment in a house of correction for up to two and a half years. That statute is general and is not tied to a specific number of minutes or a vehicle scenario, unlike states with a dedicated unattended-child-in-vehicle law.

Federal guidance vs. Massachusetts' legal minimum

Federal law under 49 CFR 571.213 (FMVSS 213) sets crash-test and construction standards a car seat must meet before sale; it does not tell a Massachusetts parent how to use the seat. NHTSA's and the American Academy of Pediatrics' guidance recommending a rear-facing position "as long as possible," up to the seat's own manufacturer limit, and a general age-and-stage progression through forward-facing and booster seats, is safety education, not part of Massachusetts' statute. Massachusetts' own law does not create rear-facing, forward-facing, or booster sub-stages at all; any rear-facing-to-2 or forward-facing recommendation seen elsewhere reflects that national guidance layered on top of Massachusetts' single restraint duty, not a separate state legal requirement.

Disclaimer: This article provides general legal information about Massachusetts' car seat law as of September 2026. It is not legal advice. Consult a lawyer licensed in Massachusetts for advice about a specific situation.

Related reading: car seat laws by state, Massachusetts DUI laws, and Massachusetts window tint laws.

Statutes cited reflect their in-force version as of 2026-09-16. Last updated: 2026-09-16.

Frequently Asked Questions

Does Massachusetts require a booster seat?

Massachusetts law does not create a separate booster seat category. It sets one 'child passenger restraint' duty for children under 8 (unless the child is taller than 57 inches), leaving the specific restraint type to the manufacturer's instructions, and then a seat belt duty for children under 13.

What is the fine for a car seat violation in Massachusetts?

The maximum fine is $25. A taxi cab operator not equipped with a child passenger restraint device is excused from that specific fine, though the underlying duty to secure the child otherwise still applies.

At what age can a child stop using a car seat in Massachusetts?

The restraint duty ends at age 8, or earlier if the child exceeds 57 inches in height. After that, the child must wear a seat belt until age 13.

Is it illegal to leave a child alone in a car in Massachusetts?

Massachusetts does not have a statute written specifically for leaving a child unattended in a vehicle. A caregiver whose conduct creates real risk to a child could still be charged under the state's general reckless-endangerment-of-a-child statute, which covers wantonly or recklessly creating a substantial risk of serious bodily injury to a child, but that law is not tied to a specific number of minutes or a vehicle scenario.