- 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.
- Australasian Society for General Relativity and Gravitation - Includes a newsletter, information on events, and links to related research groups.
- Gravitational Physics Section of EAS and EPS - Section of the Joint Astrophysics Division of the European Astronomical Society and the European Physical Society
- Gravity Research Foundation - Foundation best known for its prestigious annual essay competition.
- International Society on General Relativity and Gravitation - Includes information about the society's officers, journal and conferences.
- 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.
- Spanish Society of Gravitation and Relativity - Includes information about membership, officers, conferences and about Spanish relativity groups.
- 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.
