Objective: Alcohol consumption has been found to be common among adolescents in various studies globally. It has been associated with public health problems, high risk lifestyles, mental disorders, eating disorders, risk taking attitudes, failure in school and increased drop-out rate. This study therefore, investigated the influence of personality traits, peer group pressure and parental monitoring on alcohol use among in-school secondary students in Ibadan, Oyo State, Nigeria. Method: Survey design was adopted for the study. The researchers randomly selected Ibadan South - East Local Government Area out of eleven (11) Local Government Areas in Ibadan, for the study. Simple random sampling technique was used to select three (3) public secondary schools out of nineteen (19) secondary schools in Ibadan South-East Local Government Area while accidental sampling technique was used to select (298) in-school secondary students. Four research instruments were used to collect data. Analysis of data was carried out using mean and percentage while the hypotheses were tested using simple multiple regression and t-test statistics.