Flipped classrooms refer to teaching approaches that like usual teaching is not done inside the class. It means that before the class students watch videos that the teacher carefully chooses or prepared. The selected videos have to fulfill the required content that advances the abilities of the students in their learning. This study investigates the influence of online flipped classrooms on Iranian EFL high school students’ reading ability. To this aim, the study was done on 50 EFL 12th-grade and pre-intermediate level female students. The students were set into two groups experimental and control. A reading test was run on both groups as the pre-test, at the beginning of the study. Then, after 10 treatment sessions, the post-test was given to both groups. An independent samples t-test was run to compare the means. The outcomes illustrated the significant outperformance of the experimental group over the control group. In addition, to identify the EFL high school students’ attitudes toward the flipped classroom, the students were asked to answer an open-ended question. The results of students’ responses using thematic coding showed that most of the students had optimistic opinions regarding implementing the flipped classroom. Finally, the present study indicated that this model provides an opportunity for students to learn at their own pace and time. Therefore, it has some implications for teachers, students, and institutions which can increase student-teacher interaction in the teaching-learning process.