Reading and understanding what was read are integral parts in the life of every individual and are indispensable in the circle of educational system. However, this vital skill is what most students lack interest of. As a result, it affects their understanding in the other areas of their education endeavor. To address the problem, Robert Glaser proposed a strategy, the so called Individually Prescribed Instruction [IPI], which later on was known as Differentiated Instruction. It showcases a variety of classroom practices that accommodate differences in students’ learning styles, interests, prior knowledge, socialization needs, and comfort zones. This study, therefore, aims to determine the effectiveness of differentiated instruction strategy in improving reading comprehension among students in Sta. Rosa National High School Junior High School. The study utilized a quasi-experimental method which the 50 Grade 7 English research subjects of the study were divided into two groups, namely control and experimental. Strategies employed in these groups were different. The traditional method was practiced in the control group, while the differentiated instruction strategy was implemented in the experimental group. For data gathering, a Phil-IRI adapted test questionnaire was used as the main instrument. Another test questionnaire from Phil-IRI was used as a springboard in the implementation of strategies for both groups. Statistical treatments used for data analysis were frequency count, percentages, t-Test for Correlational Samples for Means, and t-Test for Two Independent Samples. Findings revealed that in measuring subjects’ reading comprehension skills, there was a significant difference between the posttest performances of the groups. The research subjects under experimental group performed higher than the control group. Based on the findings, the study concludes that Differentiated Instruction is an effective strategy in improving reading comprehension skills.