The International Light Cone Advisory Committee (ILCAC)
- Dedicated to efforts to solve quantum field theories by use of a special, relativity-based method known as light-cone quantization. Includes list of members and information about the committee's workshops and meetings.
- http://www.slac.stanford.edu/xorg/ilcac/

Apples with Apples
- Association of numerical relativity groups, with the aim of developing standards for comparing the groups' different simulation codes and the results obtained therewith.
- http://www.appleswithapples.org/index.html

Spanish Society of Gravitation and Relativity
- Includes information about membership, officers, conferences and about Spanish relativity groups.
- http://www.segre.es/iindex.htm

LISA International Science Community
- Website for the community of scientists involved in doing research for and with the proposed space-borne gravitational wave detector LISA.
- http://www.lisa-science.org/

International Society on General Relativity and Gravitation
- Includes information about the society's officers, journal and conferences.
- http://www.maths.qmw.ac.uk/grgsoc/

Gravity Research Foundation
- Foundation best known for its prestigious annual essay competition.
- http://www.gravityresearchfoundation.org/

Gravitational Physics Section of EAS and EPS
- Section of the Joint Astrophysics Division of the European Astronomical Society and the European Physical Society
- http://www.astro.auth.gr/gps/

Australasian Society for General Relativity and Gravitation
- Includes a newsletter, information on events, and links to related research groups.
- http://www.physics.adelaide.edu.au/ASGRG/

APS Topical Group on Gravity
- Topical interest group of the American Physical Society. Includes a brief description of the group, information about prizes, and its newsletters "Matters of gravity".
- http://www.apsgravity.org/