Social studies teachers employ discussions about controversial issues in their classrooms as an effective instructional tool in order to improve citizenship education. Therefore, teaching about controversial issues in preservice social studies programs is important for improving pre-service teachers’ understanding of their own abilities to teach about citizenship issues and their skills to teach about controversial issues in their classrooms as well. Preservice teachers ought to be encouraged to participate more in classroom discussions about controversial issues. Therefore, this study aim to understand and explain factors that affect social studies teacher candidates’ participation in classroom discussions about controversial issues and suggest how this process might be more efficient and effective in Turkey. 1957 pre-service social studies teachers from 12 different universities in Turkey participated in this study. A questionaire was used to collect data for this research. The questionaire included likert type 16 items regarding students’ personal information and factors that affect the level of participation in classroom discussions about controversial issues and one open-ended question regarding implications on how discussions can be improved in a way that help the discussions more effective and efficient. Chi-Square, frequency, and percentange tests were used to analyze the quantitative data. Inductive content analysis method was employed to analyze and code the qualitative data. The findings of the study showed that while 92.2 % pre-service social studies teachers stated that they participate in the dicussions on controversial issues when they only find it interested, 79.4 % participant pointed out that they do not participate in the discussions, if they believe they do not have enough knowledge about the topic of the dicussion. In addition, 47.5% of the participants stated that they do not want to participate in the discussions about culturally and socially sensitive issues. 40.5% pre-service teachers in the study shared that they do not have discussions with their peers who are not tolerant to different ideas and perspectives. On the other hand, 48.7% participants argued that if the discussions become a personal battles between peers, they are not comfortable sharing their ideas. 54.8% of the participants stated that even if they feel like the teacher supports one of group against other groups, they still are comfortable expressing themselves during classroom discussions; however, 32.8% participants pointed out that they do not participate in the discussions if they believe the teacher is not objective about the sensitive issue.The findings of the study show that participants’ gender, income, their parents’ education, residency, the university they attend, grade level, and high school they graduated from are contributed to their level of participation in the classroom discussions about controversial issues. Female participants stated that if they feel like they do not have enough knowledge about the discussion topic or the topic is a culturally and socially sensitve issue, they either do not participate at all or their participation is limited. However, male pre-service teachers shared that they are more concerned about peer interaction and having good relationships with their peers after the discussion is ended as well. Another finding of the study indicate that pre-service teachers from low socio-economic status shared that if they feel like the teacher’s judgement might be compromised based on students’ contradicted ideas, they rarely participate in the discussions. In addition, students whose parents have limited education (i.e., elementary level) said that they have difficulty expressing themselves during classroom discussions. Furthermore, another finding show that teacher candidates who come from big cities feel more comfortable participating in the classroom discussions about controversial issues compared to teacher candidates who come from in rural areas. In addition, results of the study indicate that level of participation in classroom discussions regarding controversial issues increased as they become sophomores and seniors. It is also important to say that culture of the universities might influence students’ response to controversial discussions. The researcher of the study found that level of participation varies based on academic culture of the universities. For example, in the universities that are considered as conservative teacher candidates participated in the discussions less than their counterparts who are enrolled in universities that are known as democratic. Therefore, these factors ougth to be carefully considered before they are educated about how to employ controversial issues as an instructional tool. The pre-service teachers suggested that they would like to be respected, the teachers should be objective during discussions, and they should not try to impose their ideas to the students.