Vehicular manslaughter is a criminal offense defined as the unintentional killing (homicide) of another person as a result of criminal negligence or recklessness while operating a motor vehicle—often while the operator is intoxicated by alcohol or drugs, engaged in a high risk activity such as street racing, or committing a misdemeanor or infraction offense (speeding) with ordinary negligence.

Vehicular manslaughter is usually a felony offense and often includes significant jail or prison time as potential punishment. Vehicular manslaughter laws vary from state to state and are generally located in a state’s statutes—often in the penal or criminal code.

In Montana, vehicular manslaughter is addressed under the term 'Negligent Homicide' as per Montana Code Annotated (MCA) 45-5-104. This statute defines the offense as causing the death of another human being through an act of negligence, which can include the operation of a vehicle. Negligent homicide in Montana is considered a felony. The law does not require the intent to kill, only that the individual acted negligently, which could involve driving under the influence of alcohol or drugs, reckless driving, or other forms of negligent behavior while operating a motor vehicle. Penalties for negligent homicide in Montana can be severe, including imprisonment, fines, or both. The specific circumstances of the incident, such as the level of negligence and whether the driver was under the influence, can influence the severity of the punishment.