The aim of the current study is to investigate the effect of using life wide learning approach on developing English language Fluency for prep. stage students in the official Language Schools. The study adopted the one-group pre-post experimental design, with a pre-post fluency test along with a triangulation method that integrates both quantitative and qualitative assessment. Participants of the study were 30 students in preparatory one from Al-Rafei official language school in Gharbia governorate, Egypt in the academic year 2023-2024. An electronic test was designed to measure the students' EFL fluency. A program based on life wide learning activities was designed to develop the students' EFL fluency. Participants' scores of the pre and posttest were statistically analyzed using t- test and the effect size was calculated. The findings revealed that the total mean scores of the participants on the post-administration of the fluency test were higher than their total mean scores on the pre-treatment. In addition, the effect size of all EFL fluency components indicated that the program based on life wide learning activities had a strong effect on enhancing first preparatory stage students' EFL fluency components.