The main thrust of the study was to investigate Peer Group Influence as a Correlate of Aggressive Behaviour among Secondary School Students in Abia State. Three research questions and three null hypotheses guided the study. The study adopted a correlational research design. The sample for the study consisted of 878 respondents drawn through a two-stage sampling procedure from 8783 (4195 male and 4588 female) senior secondary school students in Abia State. Two instruments titled â€œPeer Group Influence Questionnairesâ€ (PGIQ) and â€œStudents Aggressive Behaviour Questionnaireâ€ (SABQ) were developed by the researchers and used for the study. The instruments were face validated by three experts: one from Psychology, another fromGuidance and Counselling and the third from Measurement and Evaluation; all from the Michael Okpara University of Agriculture, Umudike. The stability of the instruments were determined using Pearsonâ€™s Product Moment Correlation Coefficient which gave reliability indices of r = .731, and r = .823 for PGIQ and SABQ respectively. Data obtained were analyzed using Pearson Product Moment Correlation Coefficient, Linear regression and multiple regression which revealed the following findings: Peer group influence to a positive high and significant extent correlate with aggressive behaviour. A positive but very low and no significant gender differences exist in the relationship between peer group influence and aggressive behaviour of the students. Among the educational implications of the findings was that aggressive behaviour depends on group influence among senior secondary school students. It was thus recommended among other things that there is need for periodic exposure of senior secondary school students to seminars on peer group influence as correlates of aggressive behaviour among Secondary School Students to enable them be guided by the implications the concepts of Peer Group Influence as relate to aggressive behaviour.
Keywords: Peer Group, Influence, Aggressive behaviour, Secondary School Students.