This study aims to examine the significant difference in reading comprehension performance after explicit instruction in morphology. This quasi-experimental study investigated specifically the effect of explicit teaching on compounding, inflectional and derivational morphological awareness upon Malaysian primary school learners' reading comprehension in the ESL context. Convenience sampling was applied in recruiting 125 pupils from two government primary schools in a suburb area. The experimental group was given the explicit instruction in morphology during their reading lessons for 12 consecutive weeks, and the control group had been taught without this intervention. After controlling for learners' pre-test scores, ANCOVA statistical result concluded that the experimental group could achieve higher scores in their post-tests, which indicated a significant difference in reading comprehension performance. Therefore, it is essential for curriculum developers to give recognition of the importance of morphology. Educational practitioners and academics should explore further the teaching of morphology in order to improve their learners' reading comprehension skill.