When a driver under 18 is charged with DUI in Montana, the case is generally heard in the same justice, municipal, or city court that hears adult traffic cases, not in youth court. Two things are different for a minor: jail is not an available punishment, and the license consequences come from several statutes at once. This page explains the court, the charge, the license, and where parents fit. It is part of our Montana DUI Guide, and it builds on our under-21 DUI page.
Which Court Hears It
The Montana Youth Court Act gives the youth court exclusive original jurisdiction over a person charged with violating a state law or local ordinance before turning 18, with a stated exception: "other than a traffic or fish and game law" (MCA § 41-5-203(1)). DUI sits in Title 61, chapter 8, which is the traffic regulation chapter. A separate statute points the same way, by setting special punishment rules for "a person under 18 years of age who is convicted of an offense under this title" (MCA § 61-8-723).
In practice that means the citation tells a teen to appear in the same court an adult would. In Missoula that is generally Municipal Court for a city police citation and Justice Court for a sheriff or Highway Patrol citation. See our page on which court hears a DUI. The procedure is the adult procedure: an initial appearance, a plea, and the right to a trial.
A minor in possession charge from the same night can go either way. Justice, municipal, and city courts share jurisdiction with the youth court over alcoholic beverage violations by a youth (MCA § 41-5-203(2)).
Which Charge: Under-21 or Adult
Most cases against a minor are filed under the under-21 section. It applies to a driver under 21 with an alcohol concentration of 0.02 or more, or with any amount of active THC, in a vehicle anywhere in the state (MCA § 61-8-1002(1)(e)). The State does not have to prove impairment.
That section is not the only one available. The impairment offense and the 0.08 per se offense apply to a person of any age (MCA § 61-8-1002(1)(a) and (b)). A 17-year-old who tests at 0.08 or more can be charged with the adult offense, and a conviction for it counts as a prior later in life. Only one conviction under the DUI statute is allowed per incident (MCA § 61-8-1002(6)), so which subsection the case ends on matters. Our comparison of MIP and under-21 DUI covers the lesser charges.
No Jail for a Driver Under 18
MCA § 61-8-723 says a person under 18 convicted of an offense under Title 61 "may not be punished by incarceration." In place of jail the court may use:
- a fine no greater than an adult could receive, and the minor may not be jailed for failing to pay it;
- revocation of the driver's license by the court, or suspension for a period the court sets;
- impoundment of the vehicle for up to 60 days, if the court finds the minor owns it or is the only person who uses it; or
- any combination of those.
The under-21 penalty statute is consistent with that. Its jail terms for second and third convictions apply only "if the person is 18 years of age or older" (MCA § 61-8-1007(3)(a)). The chemical dependency assessment and the education course or treatment still apply, regardless of age. Our page on DUI classes, assessment, and treatment explains them.
Charges and License Consequences at a Glance
| Event | Fine or fee | Driver's license | MCA |
|---|---|---|---|
| Under-21 offense: 0.02 alcohol or any active THC | $100 to $500 on a first conviction | Suspended 90 days. At least 30 days must be served before a restricted license. | §§ 61-8-1002(1)(e), 61-8-1007(3) |
| Adult DUI: impairment, or 0.08 or more | $600 to $1,000 on a first conviction | Suspended 6 months | §§ 61-8-1007, 61-5-208(2)(b)(i), 61-5-217 |
| Refusing a breath, blood, or oral fluid test | $300 administrative fee | Suspended 6 months, no probationary license | § 61-8-1032 |
| Minor in possession of alcohol (no driving needed) | $100 to $300 on a first offense, plus 20 hours of community service | Confiscated by the court for 30 days | § 45-5-638(2) |
The driving privilege of a person under 18 is subject to suspension or revocation by the Motor Vehicle Division in the same manner and for the same causes as an adult's (MCA § 61-5-217). That is why the adult periods apply to an adult charge and why a refusal carries the full 6 months. A refusal also starts a 30-day deadline to petition the district court. See our test refusal page.
On top of the Motor Vehicle Division's action, the sentencing court has its own power under § 61-8-723 to suspend or revoke a minor's license for a period it chooses. The statute does not set a length for that, so it is something a lawyer can address at sentencing.
What Parents Should Know
- The citation is your teen's, and the court date is real. A missed appearance has the same consequences as it would for an adult. Go with them.
- Civil liability can reach you. A parent or other adult must sign a minor's license application, and a minor's negligence or willful misconduct behind the wheel is imputed to the signer, who is jointly liable for damages unless a liability policy covering the minor is in effect (MCA § 61-5-108). In a crash, that makes your insurance central.
- An MIP sentence can include you. On an alcohol MIP conviction of a person under 18, the court orders the minor and the parent or guardian to complete and pay for a substance abuse information course, if one is available (MCA § 45-5-638(2)(a)).
- Let the lawyer do the talking about the facts. What your teen says to police, school staff, or an insurance adjuster is not confidential. What they tell their lawyer is.
When a Crash Makes It More Serious
Charges outside the traffic code follow different rules. Offenses such as negligent homicide and vehicular homicide while under the influence are in the criminal code, and for a youth who was 16 or older the county attorney may ask to file those charges in district court (MCA § 41-5-206(1)(b)). If anyone was hurt, get legal advice immediately. Our page on DUI with a crash or a child in the car explains the adult versions of those charges.
This page explains Montana law in general as of the 2025 Montana Code Annotated. It is not legal advice about your specific case.