A 2-phase study was conducted to develop a culturally informed measure of psychosocial stress for adolescents: the Hispanic Stress Inventory—Adolescent Version (HSI–A). Phase 1 involved item development through the collection of open-ended focus group interview data (n = 170) from a heterogeneous sample of Hispanic youths residing in the southwest and northeast United States. In Phase 2, we examined the psychometric properties of the HSI–A (n = 1,651), which involved the use of factor analytic procedures to determine the underlying scale structure of the HSI–A for foreign-born and U.S.-born participants in an aggregated analytic approach. An 8-factor solution was established, with factors that include Family Economic Stress, Acculturation-Gap Stress, Culture and Educational Stress, Immigration-Related Stress, Discrimination Stress, Family Immigration Stress, Community and Gang-Related Stress, and Family and Drug-Related Stress. Concurrent, related validity estimates were calculated to determine relations between HSI–A and other measures of child psychopathology and behavioral and emotional disturbances. HSI–A total stress appraisal scores were significantly correlated with both the Children's Depression Inventory and the Youth Self Report (p < .001). Reliability estimates for the HSI–A were conducted, and they yielded high reliability coefficients for most factor subscales, with the HSI–A total stress appraisal score reliability alpha at .92.