The purpose of this current study was to evaluate the use of a stimulus equivalence paradigm to teach emerging adults with developmental disabilities to accurately estimate portion sizes. This study also aimed to integrate nutritionally recommended foods to incorporate a socially significant component to promote health related behaviors. Three emerging adults with various developmental disabilities participated in this study. A pre/post-test embedded in a multiple baseline design across food was used to demonstrate experimental control. Results of this study indicated that all participants exhibited accurate portion size estimations following stimulus equivalence direct training trials and test of untrained relations. When asked about their perceptions of the training methods through a social validity questionnaire participants indicated that this training method were effective and acceptable. Limitations and directions for further research are also discussed.