William Lewis "Bud" Uanna (May 13, 1909 – December 22, 1961) was an American security expert, who gained prominence as a security officer with the Manhattan Project, which built the first atomic bomb during World War II. Uanna was in charge of security at the project's facility at Oak Ridge, Tennessee, and later at the 509th Composite Group, which dropped atomic bombs on Hiroshima and Nagasaki.