This research is an attempt made to assess the relationship between mental health and academic achievement among Srilankan youths. This study also explores the role of demographic variables on mental health. The sample size for this study comprised of 236 students randomly selected from Ampara district, Srilanka. The samples were between the age groups of 17 to 25 years. (Mean age = 21). The tools used for data collections were : (1) Mental Health scale by Dr.Kamlesh Sharma (2002), (2) Academic Achievement was assessed based on recent exam results of the students who participated in the study, and (3) the personal information schedule used, was developed by the researcher to relevant demographic information. ‘t’-test, ‘f ’ test, Pearson product moment correlation were this statistical analysis done. The result revealed that there is a positive correlation between Mental Health and Academic Achievement.