The Metadata Object Description Schema (MODS) is an XML-based bibliographic description schema developed by the United States Library of Congress' Network Development and Standards Office.

MODS was designed as a compromise between the complexity of the MARC format used by libraries and the extreme simplicity of Dublin Core metadata.

The Library of Congress' Network Development and MARC Standards Office, with interested experts, developed the Metadata Object Description Schema (MODS) in 2002 for a bibliographic element set that may be used for a variety of purposes, and particularly for library applications.

There is no commitment on the part of the Library of Congress to maintain compatibility between the two metadata formats beyond what is convenient to the community of MODS users.

[5] The Library of Congress carries out the application of approved changes to the schema and maintains the official web site for the standard.