Alexander "Greek" Thomson (9 April 1817 – 22 March 1875) was an eminent Scottish architect and architectural theorist who was a pioneer in sustainable building. Although his work was published in the architectural press of his day, it was little appreciated outside Glasgow during his lifetime. It has only been since the 1950s and 1960s that his critical reputation has revived—not least of all in connection with his probable influence on Frank Lloyd Wright.