This research examined the relationships between the Big Five human personality traits, favorable social conditions, and foreign language classroom speaking confidence. Four research questions were investigated concerning the validity of the Big Five for a Japanese university sample, the composition of Foreign Language Classroom Speaking Confidence, the degree to which the Big Five influenced Foreign Language Classroom Speaking Confidence, and the degree to which perceptions of classroom climate affect Foreign Language Classroom Speaking Confidence. The first stage of the research involved three pilot studies that led to the revision of the Big Five Factor Marker questionnaire and the creation of a new instrument for measuring foreign language classroom speaking confidence that included both cognitive and social factors as theorized in mainstream social anxiety research. The second stage of the research involved the collection and analysis of data from 1,081 participants studying English in 12 universities throughout Japan. Data were analyzed using a triangulation of Rasch analysis, exploratory factor analysis (EFA), and confirmatory factor analysis (CFA) in order to verify the construct validity of the eleven hypothesized constructs. Following validation of the measurement model, the latent variables were placed into a structural regression model, which was tested by using half of the data set as a calibration sample and confirmed by using the second half of the data set as a validation sample. The results of the study indicated the following: (a) four of the five hypothesized Big Five personality traits were valid for the Japanese sample; (b) Foreign Language Classroom Speaking Confidence comprised three measurement variables, Foreign Language Classroom Speaking Anxiety, Perceived Foreign Language Speaking Self-Competence, and Desire to Speak English; (c) Emotional Stability and Imagination directly influenced Foreign Language Classroom Speaking Confidence, and; (d) Current English Classroom Perception and Perceived Social Value of Speaking English directly influenced Foreign Language Classroom Speaking Confidence. The findings thus demonstrated a link between personality, positive classroom atmosphere, and foreign language classroom speaking confidence. The implications of the findings included the possibility that foreign language anxiety is not situation-specific as theorized, and that improved social relations within the foreign language classroom might help reduce speaking anxiety. / CITE/Language Arts