The Acculturation Rating Scale for Mexican Americans-II is one of the most frequently used measures of acculturation, despite lack of validation. This study analyzed the structure of the Marginality Scale of the Acculturation Rating Scale for Mexican Americans-II using data from a diverse Latino sample of residents. Confirmatory factor analysis of the Marginality Scale yielded poor model-to-data fit for the hypothesized scales. Exploratory analysis and tests of construct validity were performed to further analyze the Marginality Scale. Results indicate that the revised version needs further work and should be validated with the original intended population for the scale. The utility of the marginality concept is questioned overall considering its history of lack of clear conceptualization and validity.