Teachers' personality traits are reflected in their classroom instruction--especially in their selection of various instructional strategies, the materials they choose, and their classroom management techniques. Moreover, personality styles are positively interrelated with learning styles as well as teaching styles. In many classrooms, however, teaching styles are not well matched with the preferred learning styles of students. By understanding their students' different personality types, teachers can adjust their teaching to foster individual success. How can students' personality styles be determined? What can teachers do with the results of those assessments? This article describes a number of personality assessment tools which teachers can use to help develop differentiated teaching methods. (Contains 4 figures.)