Charles S. T. Calder (March 1891[1] – December 1972) was a Scottish archaeologist who undertook extensive explorations from the 1920s to 1950s.

He is best known for his explorations of Neolithic cairns and buildings in Shetland in the 1940s and 1950s, although his contribution to the investigative work and publications of RCAHMS during a period of over 40 years service cannot be overstated.

He saw some active service in France and Flanders with the 529th (East Riding) Field Company, Royal Engineers, although most of the fighting was over.

[2] From the mid-1920s through to the outbreak of World War II, Calder was active in the resurgence of studies of Neolithic sites in Scotland as Investigator in the RCAHMS, as were V. Gordon Childe, Walter Gordon Grant and J Graham Callander, Keeper of the National Museum of Antiquities.

In 1940 Calder conducted an emergency excavation of a broch in Caithness before it was destroyed to make way for the new airport of RAF Skitten.

[10] He saw a strong resemblance to these structures, saying, "it is almost impossible not to assume that the Maltese temples are the prototypes from which Stanydale is derived and which solve the question of its purpose.