Abstract—Emotional maturity is the ability to understand and manage one’s emotions for better adjustment in life. The objective of this study is to examine the emotional maturity of high school students and its impact on their academic achievement. The study population consist of all the high school students enrolled in Mokokchung district’ schools, including those in the rural and urban. Using the simple random sampling method, a sample of 200 students from the district was selected for the study. The Emotional Maturity Scale developed by Yashvir Singh and Mahesh Bhargava, in 2008, was employed for gathering information on Emotional Maturity. Data on the academic achievement of high school students was evaluated in the light of their previous class exam results. According to the findings of the current study, no appreciable differences has been found in the high school students’ Emotional Maturity according to their type of schools and locality; however, significant difference have been found in their Emotional Maturity based on gender. Academic Achievement and Emotional Maturity significantly correlate among the high school students in Mokokchung district of Nagaland.