For individuals with autism spectrum disorder (ASD), behavioral inflexibility can affect multiple domains of functioning and family life. The objective of this study was to develop and validate a clinical interview version of the Behavioral Inflexibility Scale. Trained interviewers conducted interviews with parents of 144 children with ASD and 70 typically developing children (ages: 3-17 years). Using exploratory factor analysis, the Behavioral Inflexibility Scale-Clinical Interview (BIS-CI) was found to be unidimensional. Reliability data indicated the measure was internally consistent ([alpha] = 0.80), achieved excellent inter-rater reliability (ICC = 0.97) and test-retest reliability (ICC = 0.87). These findings demonstrate that the BIS-CI is a reliable and valid measure to determine the functional impact of behavioral inflexibility.