This study examined the influences of both peer and parent-child relationships on suicidal ideation in adolescents with a focus on interpersonal relationships in adolescence that can act as risks as well as protective factors for youth suicide. This study analyzed 5,440 middle and high school students drawn from data, the seventh Happy Planet Index of children-adolescent in Korea, and conducted a series of logistic regressions. The results are as follows. First, both direct and indirect involvement in the school violence affects suicidal ideation as a risk factor in peer relationships. However, the quality and quantity of close friends of adolescents do not represent a protective role against suicidal ideation insofar as they are exposed to school violence. Second, adolescents who live apart from one of their parents are vulnerable to suicidal ideation than those who live with two parents. Third, very poor parent-child relationships in adolescence are not necessarily associated with suicidal ideation in adolescents. Fourth, shared time or activities between parents and adolescents in terms of family meal times are more likely to reduce suicidal ideation in adolescents than the emotional characteristics (trustworthiness or a close relationship) of parents and adolescents. The findings provide implications that frequent contact and shared activities in terms of family dining may contribute to the prevention of adolescent suicide.