The purpose of the paper is to determine the mental ability of higher secondary students in Vellore district of Tamilnadu. Thus the researcher felt the need to investigate the mental ability of higher secondary students indifferent categories of higher secondary students. From the total population, out of 280 samples the of 97 from boys, 113 girls and 70 from Coeducation of higher secondary students from the government, aided and private schools were selected to study. The results of the study indicated that higher secondary students from all the samples such as Gender, Type of School, locality of the School, Medium of School, Nature of School, Parental Occupation, Birth Order and Type of Family do not differ significantly towards mental ability.