EFL readers tend to experience a number of challenges while learning, due to a number of factors that affect how these readers achieve their learning goals. Metacognitive strategies, referring to one's deliberate, goal-directed control over cognitive enterprises, are considered crucial for assisting EFL learners to be able to accomplish comprehension while reading. Previous studies have enriched the knowledge of metacognitive reading strategies in EFL settings. However, only few investigations yielded statistically significant effects on learners' reading performance. This present study hence foresees an opportunity to shed new light on this issue by focusing on EFL learners' proficiency. The objectives of this research are twofold: exploring the effects of the metacognitive strategy instruction on the strategy awareness, and perceiving the effects of the instruction on the reading performance in taking a standardized test. Forty-three students enrolling in a private male school in Bangkok, Thailand participated in the study, lasting ten weeks. A wide range of research tools were administered: SORS, IELTS reading test, and lesson plans. The findings suggested that the students' awareness of reading strategies used in terms of sub-categories and IELTS reading test score improved with statistical significance. Pedagogical implications and suggestions for future research studies are discussed based on the findings.