Results of randomized controlled trials have demonstrated significant reductions in anxiety symptoms following cognitive behavior therapy participation. Although promising, the extent to which previous research has included families from low socioeconomic status or racially/ethnically diverse backgrounds is unknown. Aims of this study are as follows: (1) What is the race, ethnicity, and educational attainment of youth with autism spectrum disorder and their families who have participated in research examining the efficacy of cognitive behavior therapy for anxiety? and (2) How do the demographics of these participants compare to that of the United States census? A total of 14 studies were reviewed that included 473 participants. Chi-square analyses indicated that there are significant differences between the race/ethnicity of youth with autism spectrum disorder participating in cognitive behavior therapy research for anxiety and that of youth in the United States. Standard residuals indicated significant overrepresentation of White youth and significant underrepresentation of Black and Latino youth in cognitive behavior therapy research (all p-values <0.001). Similarly, there were significant differences in the educational attainment of caregivers participating in cognitive behavior therapy research, with a significant underrepresentation of caregivers from low socioeconomic status backgrounds (p < 0.001). These findings have implications for the development of cognitive behavior therapy interventions for youth with autism spectrum disorder and anxiety that are both rigorous and inclusive.