This study investigates the factors influencing adolescent students’ participation in classroom conversations. Quantitative data were collected from 3,429 primary and secondary students using questionnaires, and qualitative data were collected from 25 students using semi-structured interviews to obtain an in-depth understanding of the results of the quantitative research. Using the quantitative data, we explored the structural relationship between peers, parents, teachers, and personal factors and students’ participation in classroom conversations, including questioning, presentations, and a small group discussion. Specifically, we examined the mediating effects of students’ communication attitudes―communication efficacy, enjoyment in school talk , and empathic conversational attitudes. We hypothesized a structural model wherein perceived parents’, peers’, and teachers’ factors influence adolescent students’ communication attitudes and, in turn, students’ communication attitudes influence their participation in classroom conversations. The results showed that both communication efficacy and enjoyment of talking in school had significant positive effects on participation in classroom conversation; the direct effects were .45 and .26, respectively. Communication efficacy had the highest total effect. The indirect effects of mothers’, fathers’, and teachers’ interest in oral communication were .10, .09, and .32, respectively. Empathic conversation attitudes had a mediating effect on the relationship between the interests expressed in conversations and communication efficacy. Following the quantitative data analysis, individual interviews were conducted with 16 active participants and 9 passive participants classified on the basis of the survey results. The findings of this study show that there were differences between active and passive participants in terms of the opportunity for personal talks with teachers, the nature of parents’ interest in oral communication, confidence in public speaking, and the perception of peer responses in the classroom. These results imply that rather than focusing just on communication skills, teachers should use diverse approaches to help students positively perceive their communication capacities and support students to express empathic conversational attitudes. In addition, it is important to show a supportive interest in children speaking at home, and to create a safe and supportive classroom in school.