This study investigates the relationship among Japanese high school teachers’ beliefs, their practices, and socioeducational factors regarding communicative language teaching (CLT). A multimethods approach was used consisting of a survey, interviews, and class observations. A Teacher Beliefs Questionnaire was sent to 188 randomly selected Japanese high schools, and 139 teachers responded. Additionally, 12 English classes taught by 4 Japanese high school teachers were observed, focusing on how they used communicative activities. The same 4 teachers were later interviewed. A path model based on Borg's (2003) conceptual framework of teacher cognition was tested. The best-fitting model indicated that Student-Related Communicative Conditions directly impacted Classroom Practices, Positive CLT Beliefs indirectly influenced Classroom Practices via CLT Self-Efficacy, and Exam-Related Expectations both directly and indirectly affected Classroom Practices. Findings from the interviews and observations revealed that the participants’ learning experiences, in-service training, and contextual factors (e.g., university entrance examinations) influenced their beliefs and practices.