The aim of this investigation was to analyze the relationship between generalized self-efficacy and psychological well-being in highly vs. lowly efficient Italian adolescents from 14 to 18 year-olds. We used the Generalized Self-efficacy Scale and the short version of Psychological Well-Being Scales. Results showed positive relationships between GSES and PWB, especially with mastery, personal growth, and self-acceptance. For age, except for the autonomy, the highest scores of personal growth, relations with others, purpose in life, and self-acceptance were obtained by 16yrs. adolescents, while the lowest scores were reached by 14yrs. and 18yrs. ones. Boys expressed greater GSES and PWB than girls -specifically, mastery and self-acceptance. Additionally, highly efficient adolescents expressed higher scores in PWB, especially in mastery, personal growth, and self-acceptance, than lowly efficient ones. Conclusion: educational trainings, centred on the effects of self-efficacy on psychological well-being, could be useful to empower personal resources during the adolescence. (C) 2014 The Authors. Published by Elsevier Ltd.