The National Speleological Society (NSS) is an organization formed in 1941 to advance the exploration, conservation, study, and understanding of caves in the United States.

Originally headquartered in Washington D.C., its current offices are in Huntsville, Alabama.

The organization engages in the research and scientific study, restoration, exploration, and protection of caves.

[3][4] The Speleological Society of the District of Columbia (SSDC) was formed on May 6, 1939 by Bill Stephenson.

These include:[8] The NSS hosts a yearly convention, which is generally held in June.