A preliminary evaluation of the correspondence between functional analysis outcomes across settings was conducted with 2 children who had been diagnosed with autism and who engaged in challenging behavior. Differences across settings (a therapy room and a classroom) were demonstrated in ABAB reversal designs. Three potential patterns of results that may occur when comparing functional analyses across environments are described, and one possible explanation for the occurrence of discrepancies between environments (differing learning histories within separate environments) is offered. (Contains 1 figure.)