Current educational demand is ranking the learner among the most intellectual beings on the basis of school accountability and school achievement in the more challenging content like Science and Mathematics. The learners use their own strategies to learn the concept which are not taught to them show high achievement and know how to learn and apply their knowledge and skills actively across various learning environments. This knowledge or self awareness about their own thinking process and regulation of this knowledge is Metacognition. The effective Metacognition naturally helps to develop suitable learning strategies which encourages learners to monitor, evaluate and revise their performance showing excellent academic achievement. Considering that many students with disabilities struggle with developing strategies for learning and remembering on their own, a teacher skilled in introducing this process can make a world of difference. The present study was to find Effectiveness of Learning Strategy Instruction on Achievement in Physical Science and Metacognition of the Standard Eight Pupils of Dakshina Kannada District. The investigator has used Experimental Method with Post Test Only Parallel Group Design in the study. Findings revealed that the experimental treatment through Learning Strategy Instruction has enhanced the Achievement in Physical Science among the pupils of Standard Eight especially in terms of Knowledge and Application. Result also indicates that experimental treatment through Learning Strategy Instruction has increased the Metacognition of the pupils.