Three studies (N = 1119) were conducted to replicate and expand upon Kearney, Plax, Hays, and Ivey's seminal research on instructor misbehaviors. In study 1 (n = 233), a replication of Kearney et al.'s study revealed 43 categories of perceived instructor misbehaviors; 27 of the misbehaviors were originally identified by Kearney et al. and 16 new misbehaviors were identified in this study. In study 2 (n = 650), the Instructor Misbehavior Scale (IMS) was created to operationalize underlying dimensions of instructor misbehaviors; three dimensions (i.e., antagonism, lectures, and articulation) were uncovered through principal axis factoring. In study 3 (n = 236), a confirmatory factor analysis provided construct validity support for the three-factor IMS. Additionally, the antagonism and lectures dimensions of instructor misbehaviors were correlated negatively with student learning outcomes (i.e., affective learning, cognitive learning, state motivation, student communication satisfaction) and served as unique predictors in multiple regression analyses. Collectively, these three studies provide an updated typology along with a reliable and a valid measure of instructor misbehaviors.