William R. Dunn (May 23, 1888 – March 24, 1946) was an American actor on film and stage and in vaudeville. Dunn was born in Astoria, Long Island, the son of William R. Dunn, a ferry captain, and Martha Wentz. He had two brothers, Eddie and Stanley, who were also actors. He graduated from public schools there. Dunn debuted as an actor in 1900 with the Corse Payton Stock Company in Brooklyn. He went on to perform in vaudeville. Dunn was married to Sabel Johnson, who performed in, and wrote for, vaudeville sketches. They had a son, William Welcome Dunn.