Bicycle Helmet Laws in Montana
Last reviewed by BikeSize EditorialThis guide is for general information only and is not legal advice. Laws change - verify current rules with your state DOT or a licensed attorney before relying on this for any legal matter. Read full disclaimer.
The rule
Montana has no statewide bicycle-helmet law that applies to adult riders. Montana has no statewide bicycle helmet law for any age, and no Montana municipality currently requires helmets for general bicycle use. Federal CPSC certification (16 CFR Part 1203) applies to every helmet sold in the state.
What this means in practice
Because there's no statewide age mandate, adult riders in Montana aren't legally required to wear a helmet — but cycling-injury research still strongly recommends one. Local cities, school districts, and bike-share programs can impose stricter rules, so check the municipal code wherever you ride.
Get the fit right
Find your CPSC-certified helmet size
A helmet that meets the law but does not fit will not protect you. Measure your head circumference, then shop a size band you can trust.
Open the helmet size calculator