Microsoft Binder was an application originally included with Microsoft Office 95 designed to allow users to include several different types of OLE2.0 objects (e.g., Word documents, Excel spreadsheets, and PowerPoint presentations) integrated in one file. Originally utilized as a test host for OLE 2.0, it was not widely utilized in the field and was discontinued after Office 2000.

The file extension for Microsoft Binder files was .OBD, and the Office binder template format was .OBT

Binder files can still be opened in later versions of Microsoft Office up until version 2003, with the Microsoft Binder Support add-in, called UNBIND that can be installed through the Add and Remove programs menu, by selecting Microsoft Office, click change, add it and update. According to Microsoft Unbind is not included with Office 2007.