The current study aimed at investigating the effectiveness of an Extensive reading Remedial Program in developing prep stage students' English reading proficiency. The study adopted quasi-experimental design of the two groups .The participants of the study were 60 third year prep stage students from EL -Shaheed Samah Mobshir Prep School For Girls in EL Kanayat City who were equally divided into an experimental group and a control group. The experimental group was taught using the extensive Reading Remedial Program whereas the control group received regular instruction. The instrument of the study was a reading proficiency pre-post test. The results revealed that the extensive reading remedial program was effective in developing prep stage students' English reading proficiency.