William Purnell Lambertson (March 23, 1880 – October 26, 1957) was a U.S. Representative from Kansas. Born in Fairview, Kansas, Lambertson attended the public schools, Ottawa (Kansas) University, and the law school of the University of Chicago, Chicago, Illinois. He engaged in agricultural pursuits. He served as a member of the State house of representatives 1909-1911 and 1919–1921, serving as speaker pro tempore in 1911 and as speaker in 1919. He served in the State senate 1913–1915. He served as chairman of Kansas State Efficiency and Economy Commission in 1917. He served as a member of Kansas State Board of Administration 1923–1925. He was an unsuccessful candidate for nomination for governor in 1922 and for Congress in 1924 and 1926.