A passbook or bankbook is a paper book used to record bank or building society transactions on a deposit account.

Traditionally, a passbook is used for accounts with a low transaction volume, such as savings accounts. A bank teller or postmaster would write by hand the date and amount of the transaction and the updated balance and enter his or her initials. In the late 20th century, small dot matrix or inkjet printers were introduced that were capable of updating the passbook at the account holder's convenience, either at an automated teller machine or a passbook printer, either in a self-serve mode, by post, or in a branch.