Whidden & Lewis was an architectural firm based in Portland, Oregon, in the United States, around the beginning of the 20th century, formed by William M. Whidden and Ion Lewis. The partnership was established in 1889. Their residential buildings were mostly in the Colonial Revival style, while their commercial buildings were primarily in the 20th-century classical style. The commercial buildings often featured brick, along with terra cotta ornamentation. Many of their buildings are listed on the National Register of Historic Places (NRHP).