The OpenDocument format for file formats has been developed by the Organization for the Advancement of Structured Information Standards (OASIS) as XML-based open standards for storing and exchanging various types of data. OpenDocument was incorporated as an official ISO standard on 11 November 2006. This standard is further elaborated in OpenDocument 1.1 (1 February 2007) and OpenDocument 1.2 (29 September 2011).

The file formats are in fact ZIP compression files within which XML files and any additions such as images have been collected.

The free Apache OpenOffice software uses OpenDocument formats as standard formats. Outside of this package, OpenDocuments enjoy good support. Microsoft Office has supported OpenOffice formats since version 2007, although problems may occur with specific properties of the OpenDocuments.

In many countries, including the Netherlands, the use of open source software and OpenDocuments has been set as standard for making government documentation accessible.

OpenDocument formats are suitable for archiving, accessibility and reusability in the long term.

The OpenDocument format for text documents is OpenDocument Text (.odt). ODT is a preferred format under the Text documents file type.