The transition from adolescence to adulthood is difficult for individuals with autism spectrum disorder (ASD) and their families because they must learn to navigate the complex adult disability service delivery system. For Latinx (vs. White) families of youth with ASD, this period is especially difficult because of the systemic barriers (e.g., language and cultural differences) they face when accessing services. To support Latinx families, effective and culturally responsive supports (e.g. culturally tailored programs) are critical. To this end, the purpose of this study is to describe the cultural adaptation of a transition planning program (i.e., ASSIST) for Latinx families of youth with ASD. First, we culturally adapted the curriculum using the Ecological Validity Framework (Bernal et al., 1995) and the Cultural Sensitivity (CS) model (Resnicow et al., 1999). Then, we presented the culturally adapted curriculum to eight Mexican–American caregivers of youth with ASD. Specifically, we conducted three individual interviews with each participant (N = 24 interviews altogether) to examine their perceptions of the six sessions of the culturally adapted curriculum. Based on their feedback, changes were made to the curriculum. Overall, participants reported positive perceptions of the culturally adapted curriculum, but suggested the following recommendations: include information related to mixed-status families, add information about guardianship, and use the translation technique of borrowing for specific terms. Based on the findings, implications for research and practice are discussed.