This action research was conducted to investigate the effect of using explicit instruction in improving reading comprehension of Grade one pupils. . There are 45 participants in this study. Explicit Instruction is a teaching strategy that involves five specific procedures. This includes an introduction, modeling, guided practice, group practice, and independent practice which was used to improve reading comprehension. The study was conducted at Catalanacan Elementary School in the Division of the Science City of Munoz. The Philippines This study employed a true experimental design, specifically a two-group pretest, posttest study design. Results showed the pretest performance level of the participants was below standard. On the other hand, their performance level was meeting the standard. The test of the significant difference between the pretest and posttest of the respondents. It displays that a computed t-value of 20.13 is greater than the critical t - the value of 1.68. This means that there is a significant difference between the mean of the pretest and posttest of the respondents after the explicit instruction was used.