Professional development for teachers has been a substantial issue in contemporary educational research and policy. Yet, opportunities for professional development activities have been very limited in Turkey. In this study, we examined Turkish teachers' involvement in professional development activities by comparing their participation with the level of participation in top-performing countries in the Trends in International Mathematics and Science Study 2011, including Singapore, South Korea, Hong Kong, Taiwan, and Japan. Then, we also conducted face-to-face interviews with 13 Turkish mathematics and science teachers in order to explore their views about the current professional development opportunities for teachers in Turkey. The results of this study indicate that, when compared with teachers from Turkey, a larger proportion of teachers in the top-ranking countries participated in professional development activities in most of the sub-categories of professional development in both mathematics and science. In line with this finding, results of the qualitative analysis suggest that most of the teachers in Turkey are not happy with the quantity of professional development activities available to them. In addition, teachers believe that the quality of professional development provided to teachers is low in terms of its connection to the practice of teaching. This situation might hinder teachers' performance and negatively impact student achievement in Turkey.