We reviewed studies implementing activity schedules to decrease challenging behavior of children with autism spectrum disorders (ASD). Systematic searches of electronic databases, journals, and reference lists identified 18 studies meeting the inclusion criteria. These studies were evaluated in terms of the effectiveness of activity schedules to decrease challenging behavior on the basis of forms and purposes of activity schedules, various settings in which the activity schedule was applied, severity of ASD diagnosis, and communication abilities of the participants. Activity schedules were implemented to decrease challenging behavior in 43 participants aged three to 18 years. Activity schedules included photographs, line drawings, and videos intending to promote self-regulation, independence, transitions, or play skills. Regardless of the form and intended purpose of the activity schedule, they proved effective in reducing challenging behavior in each of the reviewed studies. There was some variation in effectiveness of the activity schedules across settings, severity of ASD diagnosis, and communication abilities. Included studies are summarized and evaluated in terms of effectiveness across the aforementioned variables. Implications and suggestions for future research on the use of activity schedules to decrease challenging behavior are discussed. (Contains 1 table.)