The research focused on the role of Locus of control on assertive behavior of adolescent. The null hypothesis stated-that there will be no statistical significant influence of locus if control on Assertive behavior of adolescent; with 80 participants drawn randomly from Abakaliki local government area Nigeria. Participants were within the age range of 10-18 years with a mean age of 14 years. Two set of instruments were used to get data. Locus of control inventory and assertiveness inventory, 2×2 factorial design, and analysis of variance ANOVA with unequal sample size was used for data analysis from which had the null hypothesis rejected, (F1, 46) = 155.16, (P<0.001) and in the second, (F 1, 46) = 1058.61, P< 0.001). It also showed that there is an interactive effect of (F1, 46) = 326.43, P< 0.001) and the critical value of 4.08. The findings of the research were discussed in relation to the implication on academic.