The responsibility of a person to pay a debt or other financial obligation. If an individual signs a promissory note, that individual usually has full personal liability for the debt. An exception is the unusual situation of a non-recourse individual loan, in which the lender agrees to look only to the collateral for recovery in the event of default.

An arrangement where all of the parties involved are each liable up to the full amount of the relevant obligation. If one party dies, disappears or is declared bankrupt the others remain fully liable. The converse is several or proportionate liability, where the parties are liable only for their respective obligations and not for the obligations of any of the other parties.