Dietary acculturation (adopting the eating patterns/practices of the host environment) of individuals who relocate to another country could be a risk factor for diet-related chronic diseases. A reliable and validated measure for the assessment of dietary acculturation may facilitate understanding of the relationship between dietary acculturation and diet-related chronic diseases in various nonnative populations. We aimed to determine the reliability and validity of a culturally sensitive Asian Indian Dietary Acculturation Measure (AIDAM) for Asian Indians. A cross-sectional survey was administered via Qualtrics Research Suite to 191 Asian Indian adults in the United States. The web survey consisted of AIDAM, a food frequency questionnaire consisting of Asian Indian (AI-FFQ) and non-Indian (NI-FFQ) foods and participant sociodemographic questions. Reliability and validity were examined through a polytomous Rasch model. Except for one item that was excluded due to misfit, 50 items were stable. The root mean square error was 0.08 for all the items, and the item and person reliabilities were 0.98 and 0.88, respectively. AIDAM was positively related to NI-FFQ (r = 0.265) and negatively related to AI-FFQ (r = -0.432) based on correlations and linear regressions (p < 0.001). Our preliminary analysis showed the AIDAM to have good reliability and validity when tested with a sample of Asian Indians in the United States. Further large studies with Asian Indians using AIDAM are needed to support our findings. This tool can be used by health professionals and researchers to determine the level of dietary acculturation as well as diet quality implications when assessing risk for diet-related diseases.