XLW is a file extension that is characteristic of the popular Microsoft Excel spreadsheet program. XLW are files used to store the layout of the program's workspace. It is a useful solution especially when working with many workbooks at the same time. After closing the program and reopening, the user does not have to set up the workspace from scratch. The XLW files also contain references to the correct spreadsheet files to be in the right place.

Excel is a Microsoft tool that is a component of the MS Office suite.