Dryad is an international open-access repository of research data, especially data underlying scientific and medical publications (mainly of evolutionary, genetic, and ecology biology). Dryad is a curated general-purpose repository that makes data discoverable, freely reusable, and citable. The scientific, educational, and charitable mission of Dryad is to provide the infrastructure for and promote the re-use of scholarly research data.

The vision of Dryad is a scholarly communication system in which learned societies, publishers, institutions of research and education, funding bodies and other stakeholders collaboratively sustain and promote the preservation and reuse of research data.

Dryad aims to allow researchers to validate published findings, explore new analysis methodologies, re-purpose data for research questions unanticipated by the original authors, and perform synthetic studies such as formal meta-analyses. For many publications, existing data repositories do not capture the whole data package. As a result, many important datasets are not being preserved and are no longer available, or usable, at the time that they are sought by later investigators.

Dryad serves as a repository for tables, spreadsheets, flat files, and all other kinds of published data for which specialized repositories do not already exist. Optimally, authors submit data to Dryad in conjunction with article publication, so that links to the data can be included in the published article. All data files in Dryad are associated with a published article, and are made available for reuse under the terms of a Creative Commons Zero waiver.

Dryad is also a non-profit membership organization registered in the US, providing a forum for all stakeholders to set priorities for the repository, participate in planning, and share knowledge and coordinate action around data policies.

Dryad is listed in the Registry of Research Data Repositories re3data.org.

Dryad enables authors, journals, societies and publishers to facilitate data archiving at the time of publication, when the data are readily available. Data in Dryad receives a permanent, unique Digital object identifier (DOI), which can be included in the published article so that readers are able to access the data. Authors can archive data in Dryad and be assured of its preservation, while satisfying journals' and research funding agencies' mandates to disseminate their research outputs.

Authors submit data to Dryad either when the associated article is under review or has been accepted for publication. The choice depends on whether the journal includes data within the scope of peer reviewer. Authors may also submit data after an article has been published.