William Jerome Flannery (September 30, 1865 – June 25, 1932) was an American songwriter known for his significant contributions to the music industry in the early 20th century. Born in Cornwall-on-Hudson, New York, to Irish immigrant parents, Jerome developed a passion for music and theater early in life. By the age of seventeen, he was performing in vaudeville and minstrel shows, where he also met Eddie Foy, a friend and frequent collaborator.

Jerome's career as a lyricist took off in the 1890s, with successes such as "He Never Came Back" and "My Pearl is a Bowery Girl." His most notable partnership was with composer Jean Schwartz, with whom he created numerous popular songs and musical shows. Their hits included "Mr. Dooley," "Bedelia," and "Chinatown, My Chinatown," the latter of which became a jazz standard. In 1911, Jerome and Schwartz founded their own sheet music publishing company, further cementing their influence in the music world.

In his personal life, Jerome married vaudeville singer Maude Nugent, with whom he had at least one child. He was also a founding member of the American Society of Composers, Authors, and Publishers (ASCAP), advocating for artists' rights. Jerome's legacy is marked by his contributions to American music and his role in the development of jazz standards.