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 Illinois, a month-to-month tenancy is recognized as a form of periodic tenancy where the tenant occupies the property with no definite lease end date and pays rent on a monthly basis. This arrangement allows for greater flexibility, as either the tenant or the landlord can terminate the tenancy with a 30-day written notice. This notice period is mandated by Illinois law and applies to both residential and commercial leases. If a tenant stays beyond the expiration of a fixed-term lease and continues to pay rent without signing a new lease, a month-to-month tenancy is often presumed to have been established under Illinois law. It's important for both parties to understand that the terms of the original lease, to the extent that they are not inconsistent with a month-to-month tenancy, may still govern the tenancy unless a new agreement is reached.