The purpose of the present study is to determine pre-service teachers' opinions on teaching thinking skills. 134 senior pre-service pre-school, English and mathematics teachers studying at a state university in Istanbul participated in the study which is designed based on survey model. A questionnaire which was developed by the researchers was used in data collection and percentage and frequency values were calculated for the data analysis. The results showed that preservice teachers thought that thinking skills could be taught and teaching thinking skills should begin in pre-school level. They regarded the mixed approach as the most effective approach in teaching thinking skills. They considered that teachers' and administrators' modeling were considerably important in thinking-friendly classrooms and schools. They believed that being open to different opinions was the most important attribute of teachers who promote thinking. Pre-service teachers perceive themselves partially competent in developing students' thinking skills in the future. However, they emphasized the need for training in teaching thinking skills at schools.