Background: A disease-specific health-related quality of life (HRQL) scale enables the impact of current and new interventions on the HRQL of teenagers with food hypersensitivity (FHS) to be evaluated. No such scale exists for teenagers with FHS living in the UK. This research aimed to develop and validate a disease-specific HRQL scale for this group, thus facilitating HRQL measurement in this population. Methods: A preliminary 51-item questionnaire was generated from interviews with 21 teenagers with FHS, the coverage and acceptability of which was refined in pre- and pilot testing (N = 102). On the basis of the field test data (N = 299), principal components analysis identified those items best measuring HRQL. Results: The final 34-item You and Your Food Allergy scale covered five domains: social well-being and independence, support, day-to-day activities, family relations and emotional well-being. The whole scale displayed excellent internal consistency (Cronbach’s α = 0.92) and test–retest reliability (ICC = 0.87). The scale correlated as hypothesised with a generic HRQL scale (PedsQL) and discriminated by disease severity, providing evidence for its construct validity. Conclusions: The You and Your Food Allergy scale is the first HRQL scale to have been developed and validated with UK teenagers with FHS. Subject to further evaluation of its psychometric properties, its development has important applications in future research into the HRQL of teenagers with FHS. Short and easy-to-complete, the scale has been designed to appeal to teenagers and is likely to be useful to facilitate discussion of HRQL issues.