Broken home has damaging effects on adolescents. Studies have reported that broken home has an influence on the aggressive behaviour of
adolescents of such home. Thus, this study examined the effectiveness of two behaviour modification therapies namely: Acceptance-Commitment
Therapy (ACT) and Rational Emotive Behaviour Therapy (REBT) on aggressive behaviour of Adolescents from broken homes in Ogun State,
Nigeria. A sample of 71 adolescents consisting of 28 male and 43 female were selected for the study using multistage sampling process. The design
used for the study was the quasi–experimental: pretest/posttest control group design. The study consisted of three groups: two treatment groups
and one control group. The first group was exposed to AcceptanceCommitment herapy (ACT), second group was exposed to Rational Emotive Behaviour Therapy (REBT), while the control group had no treatment. The following instruments were used to collect relevant data for the study, Family Structure Questionnaire (FSQ), The Adjustment Inventory for School Students (AISS) and the Buss Perry Aggression Questionnaire (BPAQ). Two hypotheses were formulated to guide the study. Data collected for the study were analysed using Analysis of Covariance (ANCOVA). The hypotheses were tested at 0.05 level of significance. The results indicated significant differences in aggressive behaviour of the adolescents as a result of the interventions. The ACT was observed to be effective in the decrease of aggression than REBT though both were significant. Male and female adolescents were observed not to differ in aggression as a result of exposing them to ACT and REBT. In the light of the findings, it is recommended among others that ACT and REBT should be adopted in decreasing aggression among adolescents from broken homes.