This review evaluates research on the treatment of challenging behavior in school settings for students with autism spectrum disorders (ASD). Electronic database searches were carried out to identify studies published between 1995 and 2005. Twenty-six studies were identified. A variety of procedures were implemented in these studies to decrease challenging behavior in classrooms. These procedures were classified into four groups: (a) antecedent manipulations, (b) change in instructional context, (c) differential reinforcement, and (d) self-management techniques. The results of these studies indicated that all four classes of procedures were generally effective in reducing challenging behavior. These results are discussed in relation to four issues: (a) the characteristics of the participants, (b) assessment procedures carried out prior to intervention, (c) the feasibility of classroom treatment, and (d) the social validity of intervention procedures. Surprisingly, the effectiveness of a procedure did not seem to be related to completion of a prior functional behavior assessment (FBA). Also, the reported measures of social validity in the studies reviewed here have elicited positive reports from stakeholders, but the utility of these measures, as they have been conceptualized, is questioned. The findings of this review suggest future research directions that are also examined.