A month-to-month tenancy is a periodic tenancy or lease in which the tenant is given possession of the leased premises with no specific expiration date and agrees to pay the landlord on a monthly basis. A month-to-month tenancy often requires the tenant or the landlord to give the other party 30 days written notice of termination of the lease.

Both residential leases and commercial leases may be month-to-month tenancies. If a residential or commercial tenant remains in the leased premises and continues to pay rent following the expiration of a lease for a longer term, there may be a new month-to-month tenancy created and recognized by law.

In Montana, a month-to-month tenancy is recognized for both residential and commercial properties. This type of tenancy does not have a fixed end date and continues until either the tenant or the landlord provides the other with a written notice of termination. Under Montana law, typically either party must give the other a 30-day written notice to end the tenancy. However, the notice period can vary if agreed upon differently in the lease agreement. If a tenant stays and pays rent after the expiration of a longer-term lease without signing a new one, a month-to-month tenancy is often presumed to have been established. It's important for both landlords and tenants to review their lease agreements and understand the specific terms and conditions that apply to their month-to-month tenancy, as well as any relevant state statutes that may govern the notice requirements and other aspects of their tenancy.