This systematic review examined 26 studies that implemented interventions to reduce stigma toward autistic people; the intervention recipients were primarily non-autistic people. Participants in the included studies were primarily White K-12 or undergraduate students. Most studies utilized one-time video or computer-based instruction, and more recent interventions tended to utilize online platforms. Studies varied in several respects: whether an autistic person was involved in the development and/or delivery of interventions, the intervention content, and the types and internal consistencies of the outcome variables. Risks of bias were prevalent. Masked outcome variables were used infrequently, and investigators were usually aware of group allocation. Among randomized controlled trials, the randomization processes were not sufficiently described, and non-randomized studies of interventions frequently did not account for confounding factors that could explain changes in stigma. Many non-randomized studies of interventions made unwarranted, causal claims about the intervention effectiveness on stigma reduction, and most studies did not sufficiently address limitations related to study design and risk of bias. The recommended areas of improvement include identifying active ingredients of interventions, measuring reliable changes in behaviors and attitudes, and targeting structural stigma. In addition, more robust procedures such as randomizing participants, using masked variables, and controlling baseline differences should be utilized.