A guarantor is a party that promises to a creditor or landlord that it will be responsible for another party’s obligations if that party fails to perform, typically in relation to payment of a debt or rent. In commercial and banking practice, the guarantor gives a guarantee (and often an indemnity) to support a borrower’s or tenant’s obligations, enhancing the creditor’s security and creditworthiness assessment.“Guarantor” is a descriptive term used across contract, banking, property and company law, rather than a concept with a single codified definition, though guarantees and suretyship are recognised and regulated by case law and, in some contexts, statute in England and Wales, Scotland, Northern Ireland and Ireland.Key legal features usually include: secondary liability (triggered on the principal’s default), writing and signature requirements for enforceability, and common exclusions or limitations on the guarantor’s maximum liability and duration. In corporate groups, guarantors frequently secure group borrowing or lease obligations.Usage of the term “guarantor” is broadly consistent across the UK and Ireland, though Scots law often uses the related concept of “cautioner”, and local rules on formation, interpretation, defences and enforcement of guarantees and indemnities can differ.