This study explored the effects of a web-based decision support system (Tutorial) for writing standards-based Individualized Education Programs (IEPs). A total of 35 teachers and 154 students participated across two academic years. Participants were assigned to one of three intervention groups based on level of Tutorial access: Full, Partial, or Comparison. Direct effects of the intervention on procedural and substantive elements of IEPs revealed that, although all groups had initial IEPs of similar quality, the Full Intervention group’s post-Tutorial IEPs had a significantly higher proportion of substantive items rated as adequate than did the IEPs of other groups. The intervention’s indirect effects were examined using student scores on the State Reading Assessment. The Full Intervention group demonstrated a higher rate of reading score gain than the other two groups during the academic year in which the IEP prepared with access to the Tutorial was implemented. Implications for educational practices and future research directions are discussed.