Even though boredom has been shown to be a distinct emotional experience that is prevalent among youth and that predicts a wide range of personal and societal problems, it remains often overlooked and poorly understood. Therefore, based on the Flemish data from the 2018 edition of the International Survey of Children's Well-Being, this article studies boredom proneness among young adolescents (average age = 12 years). Confirmatory factor analysis showed that the short version of the Boredom Proneness Scale--Child Version contains two dimensions referring to internal--a difficulty in keeping oneself interested and entertained--and external stimulation--the need for change and variety in the situations one encounters. Subsequent regression analyses demonstrated that both boredom proneness and social conditions predict aspects of subjective well-being (i.e., leisure boredom and life satisfaction). Our analyses revealed complex interactions between individual differences and social conditions with respect to aspects of well-being.