A line of credit is a credit facility extended by a bank or other financial institution to a government, business or individual customer that enables the customer to draw on the facility when the customer needs funds. An amount of credit that a financial institution makes available to a business or consumer during a specified period of time.

A line of credit takes several forms, such as an overdraft limit, demand loan, special purpose, export packing credit, term loan, discounting, purchase of commercial bills, traditional revolving credit card account, etc. It is effectively a source of funds that can readily be tapped at the borrower's discretion. Interest is paid only on money actually withdrawn. Lines of credit can be secured by collateral, or may be unsecured.

Lines of credit are often extended by banks, financial institutions and other licensed consumer lenders to creditworthy customers (though certain special-purpose lines of credit may not have creditworthiness requirements) to address fluctuating cash flow needs of the customer. The maximum amount of funds a customer is allowed to draw from a line of credit is typically called the credit limit or overdraft limit. The term credit limit is commonly used for credit cards whereas the term overdraft limit is more commonly used for bank accounts.