Introduction: This study sought to determine the combined and relative efficacy of self-efficacy, risk-taking behaviour and mental health on personal growth initiative of university undergraduates. Method: The expo-facto research design was used to conduct the study. Stratified random sampling technique was used to select 425 participants from 6 faculties of the Olabisi Onabanjo University, Ago Iwoye, in Ogun State, Nigeria. The age range of the participants was between 19 years and 29 years. The mean age and standard deviation of participants were 22.40 and 4.56 respectively, male = 175 and females = 250. Four validated instruments were used in collecting data. Multiple regression analysis (stepwise) and t-test statistical measures were utilized to analyze data. Results: The results indicated that risk-taking behaviour and self-efficacy together predicted 8.7% of the variation in personal growth initiative of university undergraduates. Mental health was not a good predictor of personal growth initiative. However, risk-taking behaviour, self-efficacy and mental health positively correlated with one another, and also with personal growth initiative. Discussion: Based on this finding, it was suggested that enhancing risk-taking and self-efficacy behaviours of university undergraduates would boost personal growth initiative that is desired for the social transformation of the 3rd World countries. (Contains 4 tables.)