Observable teacher behaviors were identified, by teachers and students in English and physical education classes, as either enthusiastic or not enthusiastic. Teachers described their own behaviors and students reported teacher behaviors by describing, in detail, specific events when teaching was perceived as enthusiastic and when teaching was perceived as not enthusiastic. Twenty enthusiastic behaviors were classified from behaviors reported by teachers and students. Participants agreed on five of the highest-ranked enthusiastic behaviors: participation, humor, encouragement, praise, and momentum. Of the 16 behaviors classified as not enthusiastic, the behavior reported most frequently by teachers was disinterest, while students more frequently reported detachment as not enthusiastic. Teachers, more frequently than students, reported behaviors pertaining to the presentation and delivery of content material. Students tended to report behaviors related to classroom climate. Behavioral categories differed between teachers of English and physical education; behaviors emphasized by teachers and students in English focused on content delivery and classroom atmosphere, while teachers and students in physical education stressed personal interaction skills. Appendixes include samples of forms used in the study, lists of enthusiastic and unenthusiastic behaviors, and charts showing frequency of their occurrence in classroom interaction. (JD)