A sublease agreement is a legal document that allows a tenant to sublet a property to someone else (subtenant). Also known as subletting.A sublease agreement is a rental contract used for rerenting a currently leased unit to a new tenant. A sublease agreement is a form that allows a tenant to rent space they have under a written contract with a landlord to someone else. Set out fair and legally binding terms as you lease your Ontario premises. Cover crucial aspects with our Sublease Agreement Sample Ontario template. A Sublease Agreement is a contract that outlines the terms of a sublease between an existing tenant and a subtenant. A sublease agreement is considered a written document that offers the lessee a chance to pass on the responsibility and rights of tenancy to another person. Download this free sample Sublease Agreement template below and have it customized for your unique legal needs today. Share this document.