The study determined the level of life satisfaction,social interest and participation in extracurricular activitiesamong the undergraduate students of University of Lagos. Italso examined relationship between life satisfaction and socialinterest and investigated deregulatory effect of life satisfactionand social interest in participation of extracurricular activities.This is with a view to ensuring that students relate well with oneanother. The study employed the survey research design.The population of the study consisted of all undergraduatestudents of University of Lagos. However, 200 undergraduatestudents were purposively selected in the Faculty of Educationand Faculty of Social Sciences using stratified samplingtechniques.An instrument titled “Questionnaire of LifeSatisfaction, Social Interest and Participation in Extra CurricularActivities among Undergraduates Students” was developed toelicit information from the respondents. Four researchquestions and two research hypotheses were generated andanswered. Data were analyzed using simple percentage,multiple regression, Spearman correlation and chi-squarestatistics. Among others, the results showed a significantrelationship between the students’ level of life satisfaction andtheir respective levels of participation in extracurricularactivities (χ2 =. 19.99, p <0.05). The results also indicatedthat there was no significant relationship between the students’levels of social interest and their respective levels ofparticipation in extracurricular activities (χ2 =. 2.13, p > 0.05).The results concluded that family/friends relationships wereparticularly strong among undergraduate students becausethey demonstrated high level of life satisfaction.