Functional communication training (FCT) is a common function-based intervention for young children with or at risk for autism spectrum disorder (ASD) to teach an alternative communicative response to replace problem behavior. While FCT is effective in decreasing problem behavior, often the communicative behavior that is taught occurs at a higher rate than a caregiver can reinforce. For this study, we first examined the effectiveness of an FCT intervention to decrease problem behavior and increase appropriate communication. The intervention was based on a trial-based functional analysis (TBFA) conducted in the home. Next, we applied two approaches for thinning the schedule of reinforcement (i.e., delay to reinforcement and chained schedules) following the FCT. For all three young children (ages 3-5 years) with or at risk for ASD, at least one function of behavior was identified for each participant using TBFA and the subsequent FCT intervention led to a decrease in problem behavior and increase in functional communication. The procedure for thinning the schedule was selected based on the function of the behavior and results showed that both were successful in maintaining low levels of problem behavior following FCT. Implications for research and practice are discussed and suggestions for future research studies are presented.