Inflexibility is a major characteristic of autism. In the present study we addressed inflexible mealtime behaviors and collected longitudinal data across 48 foods for 3 children, ages 6.4–7.8 years, diagnosed with autism spectrum disorder, for up to 22 weeks. Participants exhibited severe challenges with adherence to an extremely restricted repertoire of foods. We employed clinical replication and multiple baseline designs across participants to assess the effects of individualized reinforcement and hierarchical exposure to increase flexibility. Results showed that following intervention, all participants expanded their food repertoire and spontaneously requested new foods during follow up/generalization. Implications for clinical practice and directions for further research are discussed.