This study was conducted to find out the effectiveness of Layered Instructional Strategy (LIS) based on the Elaboration Theory given by Charles M. Reigeluth on the learning achievement of secondary school students in the subject of English. Main objectives were; to develop an understanding about instructional strategy, to ascertain the difference between layered Instructional strategy and traditional method, and to compare the learning competencies/abilities of the students taught through layered Instructional Strategy and the students who received traditional instruction. Furthermore, the influence of LIS on writing skills of students taught through LIS and Traditional Method. To achieve these objectives, two leading research questions were formulated. Students studying in class IX constituted the population of the study. The students of Class IX of Federal Government Secondary School, I-9/4, Islamabad were taken conveniently as sample of the study. The sample was divided into two groups after equating them on the basis of scores on pre-test. Each group comprised of 31 students. One group was randomly taken as experimental group and the other one as control. The treatment was given to the experimental group whereas the control group received traditional instruction. The experiment continued for 12 weeks. Post-test was administered immediate after the treatment was over to the whole sample to obtain final data. Data were analyzed through SPSS version 15.0 by applying independent sample t-test. The analysis of data revealed that the experimental group performed significantly better than the control group. LIS was found better instructional strategy when it was compared with traditional instructional technique under experimental setting.