How non-autistic people think about autistic people impacts autistic people negatively. Many studies developed trainings to reduce autism stigma. The existing trainings vary a lot in terms of study design, content, and reported effectiveness. This means that a review studying how the studies have been conducted is needed. We also looked at the quality of these studies. We collected and studied 26 studies that tried to reduce stigma toward autistic people. The studies often targeted White K-12 students and college students. Most trainings were implemented once. Trainings frequently used video or computer. Especially, recent studies tended to use online platforms. The study quality was poor for most studies. Some studies made inaccurate claims about the intervention effectiveness. Studies did not sufficiently address study limitations. Future trainings should aim to figure out why and how interventions work. How intervention changes people's behavior and thoughts should be studied. Researchers should study whether the training can change the societal stigma. Also, researchers should use a better study design.
Keywords: autism; educational psychology; intervention; risk of bias; stigma; systematic review; training.