Intervention and education programs for autistic individuals have been greatly informed by the medical model of disease/disability. Under this model, autism is seen as something to be fixed or remediated, and interventions have often focused on reducing autistic traits in an effort to get the autistic person to appear more "typical." Autistic advocates have denounced this, and there is still much debate on what kind of interventions are best for autistic individuals. A viable alternative to the medical model is the neurodiversity approach, where neurological differences such as autism are seen as a valuable contribution to human diversity and should be accepted. Though it has been argued that early intervention can in fact be compatible with the neurodiversity approach, the field still has much work to truly become neurodiversity-affirming. This dissertation discusses three ways to ensure interventions move toward being more neurodiversity-affirming: considering intervention social validity (i.e., acceptability) from the autistic perspective, gathering feedback on interventions from autistic adults, and assessing professionals' attitudes toward neurodiversity. The first paper herein is a systematic review of social validity assessment in Pivotal Response Treatment research, with an emphasis on assessment of the autistic point of view. The second is a qualitative investigation of 214 autistic adults' feedback on common intervention goals for young autistic children. The third paper presents the development and validation of an instrument designed to measure professionals' attitudes toward neurodiversity. Findings from the first two studies suggest that autistic perspectives need to be included much more frequently when designing and implementing interventions, and that professionals need to consider the importance of developing autistic identity, autonomy, and self-advocacy skills. Finally, the neurodiversity attitudes questionnaire (NDAQ) presents a valid way of measuring professionals' attitudes such that neurodiversity training needs can be assessed, which will hopefully ultimately lead to more neurodiversity-friendly interventions. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]