ObjectivesDelineating determinants of food choice within the school and home environments of adolescents might help to translate advocacy efforts to effective interventions. However, this will require the development of valid instruments that measure school and home food environmental factors systematically. We conducted a cross-sectional study to develop a valid questionnaire that evaluates the food-related environments at schools and homes (FRESH- Q) of adolescents aged 10–15 years in Mumbai, India. MethodsA preliminary draft was developed based on a review of literature, eleven focus group discussions (FGDs) with adolescents (n = 36) and parents (n = 27), and eight in-depth interviews (IDIs) with school supervisors followed by the identification of school food (SFE) and home food environment (HFE) constructs and an item pool generation. The content validity was evaluated by an expert panel and the item-wise content validity indices (I-CVI) for clarity and relevance were calculated. The questionnaire was pretested in 42 adolescents for face validity and further administered among 315 adolescents (mean age 13.2 (2.1) years) for psychometric evaluation. The principal axis method of exploratory factor analysis (EFA) established the construct validity and the internal consistency was determined using Cronbach alpha values > 0.7. A sub-sample (n = 108) completed FRESH-Q twice to estimate test-retest reliability. ResultsContent analysis of FGDs and IDIs revealed six SFE and eleven HFE constructs. The I-CVI for the majority of items were satisfactory (0.72–0.96) and the Cronbach alpha values were 0.88 for SFE and 0.92 for HFE items. The intra-class correlation coefficients ranged from 0.78–0.96 indicating good to excellent reliability. Four factors – availability, and affordability of school foods, adolescents’ perceptions of SFE, and cafeteria policies explained 76.2% of the variance in SFE items. The EFA model identified five underlying constructs for HFE items – availability, accessibility and visibility of foods at home, family dietary habits, food purchasing behaviors, parents’ perceptions and consumption patterns. ConclusionsA valid 36 item self-reported questionnaire was developed to evaluate the school and home food environments of urban adolescents in India. Further investigations in different settings are recommended. Funding SourcesNone.