Acculturation refers to the extent to which an individual immigrant (or immigrant group) acquires the customs and characteristics of a new receiving society and/or retains the customs and characteristics of the person’s or group’s cultural heritage. Different acculturation measures are often assumed to be interchangeable, although this assumption is rarely tested empirically. The purpose of the present study was to examine the overlap between 2 commonly used measures of acculturation among individuals of Latino/Hispanic ancestry in the United States, the Acculturation Rating Scale for Mexican Americans II (ARSMA-II) and the Bicultural Involvement Questionnaire-Short Version (BIQ-S). Specifically, we examined the ways in which scores from the 2 measures relate to one another, as well as similarities versus differences in the ways they predict external variables of interest (e.g., family functioning, parenting, and youth adjustment) that acculturation is known to influence. Findings indicate distinct patterns of results for the 2 measures. For instance, though the BIQ-S focuses entirely on language use and other cultural practices, the ARSMA-II more consistently relates to language variables. Further, adolescent BIQ-S cultural heritage scores related negatively to risks for and engagement in alcohol use—supporting prior findings—whereas ARSMA-II scores were unrelated to alcohol use. Given the largely nonoverlapping set of relationships of the BIQ-S and the ARSMA-II subscale scores with measures of language dominance and conflict, measures of parenting, and measures of youth outcomes, we recommend that studies utilize both of these measures to fully appraise acculturation in this population.