Hsien Wu (simplified Chinese: 吴宪; traditional Chinese: 吳憲; pinyin: Wú Xiàn; 24 November 1893 – 8 August 1959) was a Chinese biochemist and geneticist. He was the first to propose that protein denaturation was a purely conformational change, i.e., corresponded to protein unfolding and not to some chemical alteration of the protein. This crucial idea was popularized later by Linus Pauling and Alfred Mirsky. Wu left China in 1947 to reside in the United States.