Jus Tertii Law and Legal Definition

Jus tertii is a Latin term which means ‘right of a third party’. When a tenant or bailee or another in possession of property pleads that the title is in some person other than that person's landlord or bailor, they are said to set up a jus tertii.

It is also a defense in tort law against claims of possession such as detinue, or conversion. Jus tertii arguments imply that the interest of the present possessor is illegitimate by showing legitimate title in another person.

Jus tertii sometimes allow one person to enforce the constitutional rights of another. This is only possible for fundamental rights, where there is a close connection between the person whose rights are violated and the person wishing to enforce the rights.