This systematic review includes a narrative synthesis and meta‐analysis of research on the associations between primarily non‐autistic people's characteristics and their attitudes toward autistic people. Of 47 studies included in the narrative synthesis, White undergraduate students were surveyed most frequently. Demographic characteristics were the factors most frequently tested for associations with attitudes, followed by contact‐related factors (i.e., quantity and quality), knowledge about autism, trait and personality factors, and other factors that did not fit into a single category. Internal consistency was not reported for some instruments assessing raters' characteristics; some instruments had alpha levels lower than 0.70, and many characteristics of raters were measured using one‐item measures. Moreover, theoretical motivations for investigating the raters' characteristics were rarely provided. A total of 36 studies were included in the meta‐analysis, which showed that attitudes toward autistic people were significantly associated with participants' gender, knowledge about autism, and quality and quantity of their previous contact with autistic people, but not with their age or autistic traits. These findings indicate a need for more studies that focus on context‐related characteristics (e.g., institutional variables such as support/commitment to inclusion), use reliable instruments to measure non‐autistic people's characteristics, and situate their investigation in a theoretical framework.