The present study tests the effects of library use on adolescents' civic competencies for democratic citizenship in a Korean context. Utilizing data (N=1,386) from the National Youth Policy Institute (2006), the study performed multiple regression analyses to test the association of library use of adolescents with the levels of civic competencies for democratic citizenship. Teenagers' library use had a positive significant association with cognitive civic competencies while showing a negative significant association with behavioral dimension of civic competencies. Based on the findings, the author discusses policy implications for developing library service for youth.