Purpose/Hypothesis: Clinical reasoning (CR) includes thinking and decision making in clinical practice. Throughout the CR process, physical therapists (PTs) interpret data, make hypotheses or recognize patterns and illness scripts, and collaborate with patients/clients and the health care team. CR requires cognitive, affective, and psychomotor behaviors; unfortunately, clinical and academic faculties address concerns in the affective domain less often than concerns in other domains. Problems not addressed by faculty are likely to continue into clinical practice. The purpose of this qualitative study was to explore exemplary and problematic affective domain behaviors influencing CR from the perspective of PT faculty. The research questions for the study were: 1) What are PT students’ exemplary and problematic affective behaviors that influence CR?; 2) What are faculty perceptions of the cause of the behavior?; and 3) How will the behavior affect CR? Number of Subjects: 25 core faculty and 8 associated faculty. Materials and Methods: A trained facilitator using a semi-structured interview guide gathered data through 4 core faculty and 2 associated faculty focus group discussions. The discussions were recorded and transcribed for analysis with constant-comparative methods using NVivo® software. We began by comparing individually coded transcripts to develop and define codes. Data from coded transcripts were gathered into categories which led to development of themes. Results: Participants represented 6 PT education programs and over 10 areas of PT practice. The range of full-time academic service for core faculty (6 men;19 women) was < 1 to > 10 years; associated faculty (1 man; 7 women) had 2 to >10 years of academic experience. The following themes were identified. 1) Students demonstrated affective behaviors impacting development of clinical reasoning during all years of PT education in interactions with academic and clinical faculty, patients and classmates, and in clinical and classroom settings. 2) Students’ ineffective affective behaviors encompassed emotional responses and communication inappropriate for the context and disengagement from or limited reflection on learning. 3) Appropriate and inappropriate affective behaviors occurred in response to encountering complex environments and unexpected events or while receiving performance feedback. 4) Faculty identified attitudes, values, and beliefs as underlying causes for ineffective affective behavior. 5) Students’ ability to reflect in and on their actions and themselves as learners enhanced development of CR while inappropriate affective behaviors restricted their ability to do the hard work required to develop CR. Conclusions: Participants identified affective domain behaviors that influenced development of CR and discussed possible underlying causes for the behaviors. Providing feedback about students’ affective behaviors and encouraging reflection in/on action will assist students to develop effective CR. Clinical Relevance: Identifying affective behaviors that influence CR and their underlying causes provides support for PT faculty expectations and assists them to foster students’ development of CR.