A debit card (also known as a bank card or check card) is a plastic card that provides the cardholder electronic access to his or her bank account(s) at a financial institution. Some cards have a stored value with which a payment is made, while most relay a message to the cardholder's bank to withdraw funds from a designated account in favor of the payee's designated bank account. The card can be used as an alternative payment method to cash when making purchases. In some cases, the primary account number is assigned exclusively for use on the Internet and there is no physical card.

In many countries, the use of debit cards has become so widespread that their volume has overtaken or entirely replaced checks and, in some instances, cash transactions. The development of debit cards, unlike credit cards, has generally been country specific resulting in a number of different systems around the world, which were often incompatible. Since the mid 2000s, a number of initiatives have allowed debit cards issued in one country to be used in other countries and allowed their use for internet and phone purchases.

Unlike credit cards, the funds paid using a debit card are transferred from the bearer's bank account, instead of having the bearer pay back the money at a later date.

Debit cards usually also allow for instant withdrawal of cash, acting as the ATM card for withdrawing cash. Merchants may also offer cashback facilities to customers, where a customer can withdraw cash along with their purchase.