QBY is the extension given to files used by software called QuickBooks. It is a tool for financial and tax settlements. QBY files are used to store accounting data that can be imported into the program. Imported data from QBY files relate to a specific company and can be prepared, for example, by accountants.

The actual data file in the program is the QBW format, and the data export format is QBX. QuickBooks is a tool published in various versions by Intuit Inc.