This study aims to investigate the effect of learning by teaching on inquiry skills. With its explanatory sequential design, this particular study focuses on interrogating whether learning by teaching has an effect on prospective science teachers' inquiry skills and to unveil how it does so, only if it had an effect. The current research is conducted upon 47 prospective science teachers who study in a public university in Turkey and take a course termed as Special Topics in Chemistry during the Fall term of 2016-2017 academic year. The quantitative data is gathered with an inquiry skills scale whereas the qualitative data is collected via a structured interview form. While the t-Test is used in the analysis of the quantitative data, the method of content analysis is applied in the analysis of the qualitative data. The quantitative data displays that learning by teaching has a positive effect on the prospective science teachers' inquiry skills. The qualitative data indicates that a great majority of the prospective science teachers are of the opinion that learning by teaching has an impact on inquiry skills. They think that this effect occurs under three thematic dimensions; information, thinking and affective. The findings of this particular research suggest that learning by teaching can also be a method to develop inquiry skills of prospective science teachers.