This study aims to find out whether there is any positive relationship among locus of control and academic achievement of High school students in Puducherry region from a study on 380 school students. Locus of control scale developed by Levenson (1973) was used to collect the data. Results revealed significant difference was not observed in internal, external, and chance locus of control among male and female students, female students received higher mean scores for the internal, external, and chance locus of control than the male students. The students on the subjects of English, mathematics, and sciences showed significant difference on the internal locus of control with (F = 6.358, P<0.05) and significant difference was not observed on the external and chance locus of control. Chance locus of control with r = 0.138 on the meaningful level of P<0.01 and internal locus of control with r = 0.112 on the meaningful level of P<0.05 had a significant and positive relationship with the academic achievement of school students.