Booster seat requirements in Missouri
A car seat or booster until age 8.
Unless the child is at least 57 inches (4 ft 9 in) tall or weighs at least 80 lb, which ends the requirement whatever their age.
- Seat belt alone from
- age 8
- First offense
- $50
Every figure on this page was read at Mo. Rev. Stat. § 307.179 on 4 October 2026. Read the statute
What the Missouri booster seat law says
The stages below are separate rules in the statute, not one rule in steps.
| Rule | Figure | What Missouri requires |
|---|---|---|
| Car seat or booster | under 8 years | Until age 8, unless the child is at least 57 inches (4 ft 9 in) tall or weighs at least 80 lb. |
| Adult seat belt alone | from 8 years | Lawful from age 8, or once the child reaches 57 inches (4 ft 9 in) or 80 lb. |
| Penalty | $50 | $50 for a first offense. Condition The $50 is a ceiling, not a fixed sum, and it only covers part of the section. Under 307.179.3 a driver who violates subdivision (1), (2) or (3) of subsection 2, which is to say the restraint and booster stages, is guilty of an infraction and "may be punished by a fine of not more than fifty dollars and court costs". A violation of subdivision (4), the belt stage, is not fined here at all: it draws the penalty in subsection 6 of § 307.178, the general seat belt section. The charge under (1), (2) or (3) is dismissed or withdrawn if the driver shows the court evidence of acquiring a restraint or booster before or at the hearing. |
Size ends the requirement, whichever comes first. A child who is at least 57 inches (4 ft 9 in) tall or weighs at least 80 lb is out of the booster in Missouri whatever their age. A child who has not reached that stays in one until age 8. The size is an escape from the age rule rather than a second thing that also has to be true. Missouri gives more than one, and meeting either is enough.
Where this and size guidance disagree, follow the stricter one. A belt that crosses the neck rather than the middle of the chest is worse protection than a booster even where the statute allows it.
The statute
Missouri sets this in Mo. Rev. Stat. § 307.179. Read it at the source.
This is information, not legal advice. A city or county in Missouri can set a stricter rule than the state one, and an officer enforces the text of the statute rather than a summary of it. Where this page and the statute differ, the statute is right and this page is a bug.
Where this comes from
- Statute
- Mo. Rev. Stat. § 307.179
- Source
- revisor.mo.gov
- Jurisdiction
- Missouri (MO), state law only
- Last reviewed
- 4 October 2026 0 days ago
- Read at the statute
- 4 October 2026
- Signed off by a person
- Not yet
- Amendment history
- L. 2006 S.B. 872, effective 28 August 2006