Charles Piazzi Smyth (1819 - 1900), was Astronomer Royal of Scotland from 1846 to 1888.

Born in Naples, he was the son of astronomer Admiral William Henry Smyth.

He researched wet collodion process photography and infrared astronomy, and was notable for advancing the theory (in his book Our Inheritance in the Great Pyramid) that the Great Pyramid of Giza was a repository of prophesies which could be revealed by detailed measurements of the structure.