If you have a great credit score and want to keep it that way–NEVER cosign on ANY loans for anyone! It sounds a bit harsh, but cosigning puts you on the hook right alongside the borrower. If they miss a payment your credit score could tank, the lender will seek you out for the money, and it might affect your relationship. Bonus tip for parents: If your college student needs a co-signer on a private loan, check to see if your kid has maxed out federal loan, grant, and scholarship options first.