In many lower-income countries, there is a paucity of assessment services for autism spectrum disorders (ASD)., Guidelines will be provided for conducting cross-cultural assessments in the context of limited validated resources in Tanzania. By examining behavioral, social, and adaptive differences we were able to provide differential diagnostic evaluations aligning with best practice standards for 41 children in Tanzania age 2–21 years. We describe the utility of a flexible, behavioral observation instrument, the Childhood Autism Rating Scales, Second Edition (CARS2), to gather diagnostic information in a culturally sensitive manner. We observed that the ASD group was characterized by significantly higher scores on the CARS2, F = 21.09, p < .001, η2 = .37, than the general delay comparison group. Additional recommendations are provided for making cultural adaptations to current assessment instruments for use in a country without normed instruments, such as Tanzania.