Ralph D. Anderson (October 21, 1924 – October 24, 2010) was an American architect from Seattle, Washington. He was a founder of Ralph Anderson and Partners, later Anderson Koch Smith. Although much of his work is modernist, he is also strongly associated with preservationism. He was an early and significant contributor (including as an investor) to the restoration of Seattle's Pioneer Square neighborhood, and also participated in restoration projects along First Avenue in the Pike Place Market Historical District in the 1970s.