This thesis examines aspects of adolescent family mealtimes and psychopathology among both non-clinical (adolescents and mothers of adolescents) and clinical (adolescents with anorexia nervosa (AN)) samples. It contains seven studies employing quantitative methodology, which address three broad aims. First, to examine relationships between aspects of family mealtimes and psychopathology among adolescents. Second, to examine links between family mealtime emotions and psychopathology among mothers of adolescents. Finally, to examine associations between specific parental mealtime interactions and adolescent outcomes during a therapeutic meal session for adolescents with AN. Self-report questionnaires were completed by non-clinical adolescents and mothers of adolescents to examine associations between characteristics of family mealtimes (mealtime environment, mealtime emotions and parental feeding practices) and eating psychopathology, anxiety and depression. In addition, observational analyses were conducted on recordings of the family meal session (session two) of Family-Based Treatment (FBT) for adolescent AN. Key findings from this research include: identifying a new factor structure for the Eating Disorders Examination Questionnaire when used in research with adolescents; developing a measure to assess mealtime emotions in both adolescents and their parents; and, identifying the feeding strategies used by parents of adolescents with AN during the family meal session of FBT. Overall, the findings reported on in this thesis suggest that family mealtimes may have an important protective role in adolescent psychopathology. In addition to providing frequent family mealtimes, families should be encouraged to concentrate on the positivity of the mealtime environment and emotional experience, which may help to promote psychological well-being, and lower levels of eating psychopathology among adolescents. In relation to family mealtimes within adolescent AN, the findings increase understanding of the types of mealtime strategies parents use with their adolescent child to encourage food consumption during the family meal session of FBT. Furthermore, the research findings highlight that certain strategies may be effective in promoting eating during the session and weight gain later on in treatment. Consequently, such findings might provide a focus for therapists when supporting and coaching parents during the family meal session.