Car seat & booster law
Massachusetts
Verified · JUN 2026Quick answer · Massachusetts
A car seat or booster is required until your child is 8 years old or taller than 4'9".
A child under 8 must be fastened and secured in a child passenger restraint unless they are more than 57 inches tall. Children 8 to 12 must wear a safety belt.
Car seat law checker
The legally required restraint, by state.
General information, not legal advice.
SeatCheckerRequired vs recommended
What the law enforces, and what pediatricians advise. They are not the same.
The law requires
Minimum, or it's enforceable
- Rear-facing until
- Not specified by law
- Booster until
- Age 8 or 4'9"
- Back seat
- Not required
Pediatricians recommend
AAP — safer, not the law
- Rear-facing until
- To seat limit (often age 2+)
- Booster until
- 4'9" — typically age 8–12
- Back seat
- Until age 13
AAP guidance is a safety best practice and is separate from Massachusetts's legal minimum. Pediatricians recommend keeping a child in each stage longer than the law requires.
Every stage, by the law
Dual units shown throughout (in + cm, lb + kg). Rows marked Guidance are best practice, not a statutory requirement in Massachusetts.
| Stage | Age | Height | Weight | Citation |
|---|---|---|---|---|
| Rear-facing | Infant (per seat) | — | — | Guidance |
| Forward-facing | Toddler (per seat) | — | — | Guidance |
| Booster | until 8 yr | < 4'9" / 145 cm | — | Mass. Gen. Laws ch. 90, § 7AA |
| Seat belt | 8 yr + | or ≥ 4'9" / 145 cm | — | Mass. Gen. Laws ch. 90, § 7AA |
| Back seat | Recommended < 13 | — | — | Guidance |
- Age
- Infant (per seat)
- Age
- Toddler (per seat)
- Age
- until 8 yr
- Height
- < 4'9" / 145 cm
- Age
- 8 yr +
- Height
- or ≥ 4'9" / 145 cm
- Age
- Recommended < 13