BSGBoosterSeatGuide

State law page

Missouri Booster Seat Laws & Requirements (2026)

Under 4 yrs or under 40 lbs in child safety seat | 4-7 yrs and 40-80 lbs and 4'9" or shorter in child safety seat or booster seat | At least 80 lbs or taller than 4'9" in booster seat or safety belt

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FieldMissouri snapshot
Age requirementUnder 4 yrs or under 40 lbs in child safety seat | 4-7 yrs and 40-80 lbs and 4'9" or shorter in child safety seat or booster seat | At least 80 lbs or taller than 4'9" in booster seat or safety belt
Height requirementSee child-restraint rule; includes height language where listed.
Weight requirementSee child-restraint rule; includes weight language where listed.
Fine / penaltyVerify fine with state source; GHSA notes first-offense fines vary by state.
Last checkedGHSA reviewed by SHSOs June 2025; extracted 2026-07-23
Verification levelIndex source; official state verification pending
Child restraint requiredUnder 4 yrs or under 40 lbs in child safety seat | 4-7 yrs and 40-80 lbs and 4'9" or shorter in child safety seat or booster seat | At least 80 lbs or taller than 4'9" in booster seat or safety belt
Adult safety belt permissibleAt least 8 yrs and 80 lbs or taller than 4'9"
Verification levelIndex source; official state verification pending

Sources

Law and source links

Index source: https://www.ghsa.org/state-laws-issues/child-passengers

Statute/source text: GHSA child passenger law summary; Safe Kids state law tracker cross-check

Safety guidance

Even when Missouri law allows a seat belt, NHTSA, CDC, and AAP guidance may still recommend a booster until the vehicle belt fits properly.

Requirements guide

Understand age, height, weight, and seat belt fit.

Read requirements

Age guide

See when children typically start and stop using boosters.

Read age guide