An attempt to develop a predictive model of teacher militancy using the Automatic Interaction Detection technique is described. By employing teacher background characteristics and attitudes toward teaching, the resulting model explains a significant amount of the variation in the degree of teacher militancy in a medium size, midwestern city with an NEA affiliate as a collective bargaining agent. In addition to model development, the findings of this study seriously question the often assumed proposition that union militancy is inimical to the professional status of teachers. (Author)