Although emotion and its regulation have been linked to children's general psychopathology, it has only recently been studied in relation to childhood anxiety disorders. In this study, the authors examine the relationship between various inputs of emotion regulation and anxiety in a clinical sample of youth. Participants (N = 112) were administered a battery of questionnaires that assessed for negative emotionality, emotion expression style, and familial affective expression. Participants also took part in a structured diagnostic interview to assess for clinical levels of anxiety. Results of standard multiple regression analyses indicated a relationship between all three components of the emotion in question. Moderator analyses revealed that age, but not gender, affects the relationship between negative emotionality and self-reported anxiety symptomatology. Results of mediation analyses suggested that emotion expression influences the relationship between negative emotionality and anxiety in older participants (ages 13-17), whereas the direct effect of negative emotionality and anxiety is maintained for younger participants (ages 8-12). (Contains 4 tables and 1 figure.)