What Is a Guarantor or Co-Signer on a Lease?

By Erin Heck, Director of Partnerships, ReletMe · Reviewed November 2026

A guarantor or co-signer is a person who signs an agreement to cover specified lease obligations if the renter does not meet them.

The two labels are often used together, but the duties can differ. A co-signer may be directly responsible with the tenant; a guarantee may describe when and how the landlord can seek payment from the guarantor. Read the agreement rather than relying on the label.

What might a guarantor have to pay?

The contract may cover rent, certain fees, damage, or other obligations. It may also explain whether the guarantee continues through renewals or changes. Signing without occupying the apartment does not necessarily limit the financial duty. Ask for a complete copy of every signed document.

What happens to the guarantee during reletting?

A replacement renter may need their own guarantor, but that does not prove the original one is released. An assignment can leave existing duties in place. A new lease or a tenant’s release may not clearly address a separate guarantee. Ask the landlord whether the guarantee ends, on what date, and whether past balances remain.

What should you keep in writing?

• The lease and guarantee as signed.
• The approved transfer or new tenancy terms.
• Express confirmation of the guarantor’s release, if agreed.
• The final balance and payment records.

If the wording is unclear, seek local legal advice before signing a replacement agreement or assuming all risk has ended. ReletMe connects renters but does not approve guarantees or release co-signers.

When the transfer date changes, check whether the release date changes as well. Do not assume the renter’s permission to leave answers the guarantee question. Ask the landlord to address both people’s obligations explicitly, and keep the final reply with the original contract so a later demand can be checked against the same documents.