Purpose: Negative behavior is a picture of individual development experiencing problems, adolescents who develop will certainly show positive behavior. In fact, today many teenagers show negative behavior, one of which is aggressive behavior. This study aims to determine the effect of loneliness and the absence of father's role on aggressive behavior. Method: This type of research is quantitative research, researchers use an aggressive behavior scale, a loneliness scale, and a father's role absence scale. The sampling technique used Non-probability sampling with accindental sampling technique. The samples in this study were male and female adolescents throughout Indonesia, aged 10-24 years, unmarried, had complete parents, divorced parents, and the father died. The data analysis technique in this study used product moment for hypothesis analysis. Result: The first hypothesis of Loneliness with Aggressive Behavior in adolescents obtained a product moment correlation value of 0.734 (p <0.01). Second hypothesis, the relationship between the Absence of Father's Role with Aggressive Behavior in adolescents obtained a product moment correlation value of 0.729 (p <0.01). The effective contribution of the Absence of Father's Role with aggressive behavior in adolescents is 53.2%. The results of multiple linear regression analysis data to prove the third hypothesis, have an influence between Loneliness and Absence of Father's Role together with Aggressive Behavior obtained F of 162.637 (p <0.05), the effective contribution of Loneliness and Absence of Father's Role with Aggressive Behavior is 62.3% while 37.7% is determined by other variables not measured in this study. Conclusion: This study proves that there is a positive and significant influence between loneliness and aggressive behavior, stating that the first hypothesis is accepted, the higher the loneliness obtained by adolescents, the higher the aggressive behavior, and vice versa. The existence of a positive and significant influence between loneliness and the absence of father's role with aggressive behavior simultaneously, states the third hypothesis is accepted.