Self-esteem is a protective factor in both physical and mental health. Low self-esteem in adolescence is correlated with a wide spectrum of mental disorders both through internalising (e.g., anxiety, depression) and externalising problems (e.g., aggression). This thesis adopted a positive psychology mixed methods approach and reports three studies investigating domain-specific self-esteem. The first study investigated the self-esteem of two samples of vulnerable adolescents through assessment and Life Story Interviews. Results demonstrated spiky domain specific profiles for both adolescents with dyslexia and adolescents disengaged in school and at risk for becoming 'NEETS' - Not in Education, Employment or Training. Narratives exposed shared themes that may potentially underpin discrepancies in self-esteem. The second study explored the promotion of selfesteem through a school-based intervention focussing on 'positive emotions' in the past (gratitude), present (recognition and use of character strengths) and future (hope). There was little evidence to suggest reliable improvement in academic, general, parental and social self-esteem domains, however some benefit was demonstrated in personal and global self-esteem, especially for females and those with low-level baseline scores. The third study identified predictors of self-esteem domains from an online questionnaire circulated to a large sample of typically developing adolescents. Regression analyses indicated strengths (behavioural, emotional, personal, contextual and character) variables in the final regression equation explained 61.0% of the variation in general self-esteem, 54.0% in personal self-esteem, 58.9% in academic self-esteem, 56.0% in parental self-esteem and 49.0% in social self-esteem. After controlling for demographics, a constellation of 18 strengths were identified with the strengths of "knowing yourself" and "creativity" as universal predictors. This research highlights the importance of context, creativity and identity formation in self-esteem development and extends the literature on strengths predictors identified for potential inclusion in interventions targeting adolescents vulnerable for being at risk of low esteem.