The American Clarinet School includes approaches to clarinet playing from European immigrants who instilled their musical style and ideas in the first generation of American-born clarinetists. Some of the first influential pedagogues from Europe include Daniel Bonade (1896-1976), Gustave Langenus (1883-1957), Gaston Hamelin (1884-1951), and Simeon Bellison (1881-1953). Even though they inspired many ideas of the American approach to clarinet, they were known in their time as performers rather than teachers first. The aim of this dissertation is to provide further examination into the modern clarinet professorship in the United States by examining three of the first generation of American-born clarinet professors and their contributions to pedagogy: Keith Stein (1908-1980), William Stubbins (1911-1975), and Himie Voxman (1912-2011). Topics discussed include embouchure, hand position, articulation, technique, expression and phrasing, equipment, teaching beginners, and repertoire.