The purpose of this study is to determine whether flipped learning contributes to the development of preservice Turkish teachers' written expression skills and, if it does, the extent of this contribution. To this end, first-year students attending the Turkish teaching department in a public university in Turkey were allocated to an experimental or a control group (35 students in each) on a volunteer basis, and an experimental study was conducted. In this study, the embedded mixed-research method was selected. In order to collect the quantitative data, samples of informative and narrative texts were used at the beginning and at the end of the term. The analyses revealed that the students in the experimental group demonstrated significantly higher development in the case of both types of texts than the control group students. In order to collect the qualitative data, three students from the experimental group and three students from the control group were selected, whose writing processes were video recorded and then analyzed each week. The findings obtained from the analysis of both the quantitative and the qualitative data revealed that flipped learning is highly effective in terms of developing preservice Turkish teachers' written expression skills.