Charles Piazzi Smyth was a British astronomer who was Astronomer Royal for Scotland from 1846 to 1888; he is known for many innovations in astronomy and, along with his wife Jessica Duncan Piazzi Smyth, his pyramidological and metrological studies of the Great Pyramid of Giza.

Pyramidology refers to various religious or pseudoscientific speculations regarding pyramids, most often the Giza pyramid complex and the Great Pyramid of Giza in Egypt. Some "pyramidologists" also concern themselves with the monumental structures of pre-Columbian America, and the temples of Southeast Asia.