Increased accountability in education has resulted in a focus on implementing interventions with strong empirical support. Both student outcome and treatment integrity data are needed to draw valid conclusions about intervention effectiveness. Reviews of the literature in other fields (e.g., applied behavior analysis, prevention science) suggest that most researchers fail to report treatment integrity data. The purpose of this study was to review the treatment integrity data reported in all experimental intervention studies published in four school psychology journals between 1995 and 2008. Results indicate that a majority of published studies do not include a definition of the independent variable and half do not include quantitative treatment integrity data. (Contains 1 figure.)