This site is a virtual reference work on the First World War. The multi-perspective, open-access knowledge base is the result of an international collaborative project involving more than 1,000 authors, editors, and partners from over fifty countries.

This site is a pan-European collection of original First World War source material, including letters, diaries, photographs, films, postcards, and official documents.

A compilation of resources on World War I from the National Archives and Records Administration, including links to external sites.

The National World War I Museum and Memorial is America's leading institution dedicated to remembering, interpreting and understanding the Great War and its enduring impact. The site contains an interactive timeline and resources for educators and students, including primary sources.

The U.S. Army Center of Military History provides the full-text of online books related to American involvement in World War I.

The Commission is responsible for planning, developing, and executing programs, projects, and activities to commemorate the centennial of World War One. This site links to a wide range of digital materials on the war, including resources for teachers and researchers.

Published in 1948, this 17 volume set compiles key documents, maps, and records for the American Expeditionary Forces (AEF) from the start of the American involvement in World War I through the occupation of Germany.

This BBC site contains a wide variety of material on World War I, including a timeline, essays, films, audio, and photographs.

This GPO LibGuide provides a variety of United States Government resources which many be used to study World War I through links to exhibits, teaching guides, primary, and secondary sources.

An archive of primary source documents from World War I compiled by volunteers of the World War I Military History discussion group.

The British Library’s site offers curated access to nearly 500 historical items related to World War I. Collection items are complemented by over 50 newly commissioned articles from leading experts, short films and interviews with academics and authors, and a dedicated teachers’ area.