In finance, a loan is the tender of money by one party to another with an agreement to pay it back. The recipient, or borrower, incurs a debt and is usually required to pay interest for the use of the money.

The document evidencing the debt (e.g., a promissory note) will normally specify, among other things, the principal amount of money borrowed, the interest rate the lender is charging, and the date of repayment. A loan entails the reallocation of the subject asset(s) for a period of time, between the lender and the borrower.

The interest provides an incentive for the lender to engage in the loan. In a legal loan, each of these obligations and restrictions is enforced by contract, which can also place the borrower under additional restrictions known as loan covenants. Although this article focuses on monetary loans, in practice, any material object might be lent.

A secured loan is a form of debt in which the borrower pledges some asset (i.e., a car, a house) as collateral.

A mortgage loan is a very common type of loan, used by many individuals to purchase residential or commercial property. The lender, usually a financial institution, is given security – a lien on the title to the property – until the mortgage is paid off in full. In the case of home loans, if the borrower defaults on the loan, the bank would have the legal right to repossess the house and sell it, to recover sums owing to it. Loan modification can avoid defaults.

Similarly, a loan taken out to buy a car may be secured by the car. The duration of the loan is much shorter – often corresponding to the useful life of the car. There are two types of auto loans, direct and indirect. In a direct auto loan, a bank lends the money directly to a consumer. In an indirect auto loan, a car dealership (or a connected company) acts as an intermediary between the bank or financial institution and the consumer.

The interest rates applicable to these different forms may vary depending on the lender and the borrower. These may or may not be regulated by law. In the United Kingdom, when applied to individuals, these may come under the Consumer Credit Act 1974.

Interest rates on unsecured loans are nearly always higher than for secured loans because an unsecured lender's options for recourse against the borrower in the event of default are severely limited, subjecting the lender to higher risk compared to that encountered for a secured loan. An unsecured lender must sue the borrower, obtain a money judgment for breach of contract, and then pursue execution of the judgment against the borrower's unencumbered assets (that is, the ones not already pledged to secured lenders).

In insolvency proceedings, secured lenders traditionally have priority over unsecured lenders when a court divides up the borrower's assets. Thus, a higher interest rate reflects the additional risk that in the event of insolvency, the debt may be uncollectible.

Demand loans are short-term loans that typically do not have fixed dates for repayment. Instead, demand loans carry a floating interest rate, which varies according to the prime lending rate or other defined contract terms. Demand loans can be "called" for repayment by the lending institution at any time. Demand loans may be unsecured or secured.

A subsidized loan is a loan on which the interest is reduced by an explicit or hidden subsidy. In the context of college loans in the United States, it refers to a loan on which no interest is accrued while a student remains enrolled in education.