This paper investigates the effects of three different types of prewriting instruction on Turkish students' L2 writing production capabilities. This mixed method study was carried out with 45 Turkish EFL students enrolled at a state university. Students were allocated into three groups randomly. In the control group the prewriting phase was carried out with monologic instruction in L2, while in one of the experimental groups, it was done with dialogic instruction in L2 and in the second experimental group, dialogic instruction was conducted in L1. Data were collected by means of pre-and post-writing tasks of the students and semi-structured interviews, and analyzed with Kruskal-Wallis and Mann Whitney tests and through pattern coding, respectively. The statistical results indicated that the group who used their L1 during pre-writing stage with the help of dialogic instruction had higher mean scores than the group who was instructed monologically and the group who was instructed through dialogic instruction in L2.