This study examines generational differences and similarities between adolescents and adults. A total of 2,548 participants (982 adolescents and 1,566 adults) completed a survey developed by the present researchers, in addition to the self-efficacy subscales developed by Bandura(1997). The results indicated significant differences between adolescents and students in terms of attitudes, values, beliefs, and behavior. Adolescents reported generational gap with adults in social life, while adults perceived generational gap pertaining to academic achievement. In terms of values and behavior, adolescents were much more liberal, while adults were much more conservative. More specifically, adolescents valued self-development, wealth, and fame, while adults valued altruistic goals. In terms of desired occupation, adolescents preferred the entertainment business, while adults preferred professional careers. Adults scored higher on self-efficacy subscales, and both adolescents and adults perceived adults to be more self-efficacious. When dealing with intergenerational conflict, adolescents are more likely to avoid the problem, while adults attempt to actively solve the problem. In terms of musical preference, adolescents preferred Rap and Hip-Hop music, while adults preferred nostalgic Korean music. Adolescents were more likely to use computer and handphones. In addition to these generational differences, several were several similarities. Both samples valued family harmony, progressive ideals, role differentiation, and self-regulatory coping strategies. Finally, implication of these results are discussed.