English language is a way and basic requirement for the academic development of a person. Through English education, prosperity can be brought on to an individual, society and nation. Teaching methods are constantly being changed, new ones are developed and old methods have undergone a renaissance. Today's educational process requires teaching strategies that put student interest and curiosity first, acknowledging student voice central to learning experience." This paper describes about an instructional strategy, just in time which satisfies the need of the hour in all aspects. Just-in-Time Teaching (JiTT) is a web-based classroom strategy that combines active learning classroom activities and world wide web resources that are used to enhance the classroom environment. It is an interactive engagement pedagogical strategy. This strategy uses Web based "Warm Up" assignments due before class to stimulate critical thinking and create feedback loop between teachers and students. By examining responses to "Warm Up" exercises before class, teacher can determine students' prior knowledge and misconceptions and directly address these misconceptions while discussing course content in the class. JiTT strategy incorporates active learning approaches by moving the content transfer element of the course to pre-class preparation and helps the students to grasp the concept with greater understanding through a variety of sessions namely Warm ups, Puzzles and Good for. For finding the effectiveness of JiTT strategy, the investigator selected experimental method in a sample of 30 secondary school students in Kottayam District. In this study the investigator selected two variables one is considered as the independent and the other as dependent variable. The independent variable is JiTT strategy and the dependent Variable is Achievement in English respectively. Tools used for the study are JiTT strategy platform and Achievement pretest and post test in English. After the analysis of collected data it proved that JiTT made a positive impact in students achievement in English. From this study it is identified that teachers need to have a deeper understanding and need to apply innovative strategies like JiTT in teaching to tackle the capacities and capabilities of 21st century students