The Individuals with Disabilities Education Improvement Act requires that functional behavior assessments be conducted under certain circumstances for students with disabilities. Functional assessments may include indirect assessments (e.g., rating scales, interviews), direct-descriptive assessments (e.g., direct observations with conditional probabilities), and/or experimental functional analyses. Despite being legally required in schools, and consequently commonly conducted, there is limited research establishing the technical adequacy of indirect functional assessment instruments. This review provides an update on the availability and status of indirect functional assessment instruments available for school-based use. Results of the review are consistent with previous reviews identifying deficiencies in existing instruments. In particular, indirect functional assessment instruments for school-based use lack sufficient evidence for temporal stability, internal consistency, inter-rater reliability, treatment utility, and social validity. Results of this review are discussed in terms of directions for future research and implications for applied practice as they relate to school-based functional assessments.