At times, all children and youth can struggle with challenging behavior. If a challenging behavior interferes with the learner's ability to learn, then a functional behavior assessment (FBA) is needed. FBA can be used when the intensity, duration, or type of interfering behavior creates safety concerns or impacts a child's development. An FBA assists the IEP [individualized Education Program] team in understanding the function or purpose of a specific interfering behavior. Data collection is an essential component of FBA. This evidence-based practice (EBP) overview on FBA includes the following packet components: (1) Overview; (2) Evidence-base; (3) Step-by-Step Guide; (4) Implementation Checklist; (5) Data Collection Sheets; (6) Tip Sheet for Professionals; (7) Parent Guide; (8) Additional Resources; (9) CEC Standards; and (10) Module References. [This brief was co-written by the Autism Focused Intervention Resources and Modules (AFIRM) team.]