Except for New Hampshire, all states and the District of Columbia require adult front-seat occupants of motor vehicles to use seat belts. Adult rear-seat passengers are also covered by the laws in 31 states and the District of Columbia. Children are covered by separate laws.

State seat belt laws are divided into two categories: primary and secondary. Primary seat belt laws allow law enforcement officers to stop a motor vehicle and to issue a ticket or citation to a driver or passenger for not wearing a seat belt without any other traffic offense having occurred. Secondary seat belt laws only allow law enforcement officers to issue a ticket or citation for not wearing a seat belt when there has been another traffic offense by an occupant of the vehicle for which the occupant may be issued a ticket or citation.

In Maine, seat belt use is mandated by law under Title 29-A, Section 2081 of the Maine Revised Statutes. Maine has a primary seat belt law for all front-seat occupants, which means that law enforcement officers can stop a vehicle and issue a citation solely for a seat belt violation without the need for any other traffic offense to have occurred. The law requires all passengers aged 18 and older to wear a seat belt. Additionally, Maine law requires all passengers under 18 years old to be properly restrained, regardless of their seating position in the vehicle. For children, Maine has specific child restraint laws that require appropriate child safety seats or booster seats depending on the age, weight, and height of the child. Violation of Maine's seat belt laws can result in fines and, for child restraint violations, points on the driver's license.