OTT is a text file containg page templates used by OpenOffice and LibreOffice word processors. OTT file serves as a template for ODT files created by the user.

OTT files are useful when working with multiple documents with same formating. OTT files are therefore very convenient as templates for such types of document as company letterhead, correspondence, newsletter, and academic paper. Besides formatting, OTT files can also store information about fonts as styles.