The aim of this study was to investigate whether high school students' writing self-efficacy perceptions differ based on their gender, grade level, type of high school and the number of books they read annually. A total of 585 students (Females = 270; and Males = 315) studying in the ninth and tenth grade classes from high schools of different type participated in the study. The results showed that high school students' self-efficacy perceptions differed based on their gender, grade level, school type and the number of book they read annually. This difference was observed in the writing stages of planning, drafting, revision and modification. Consequently, it was concluded that reading books positively affected individuals' writing self-efficacy.