The present study utilized multiple-baseline and multi-probe across participants designs to measure both fidelity and efficacy of caregivers as primary interventionists when using trial-based functional analysis (TBFA) procedures. Participants included any caregiver of a child with a medical or educational diagnosis of autism and challenging behavior. Caregiver fidelity of implementation of TBFA procedures was measured across three phases: baseline, training, and independent implementation or generalization. Within the implementation phase, caregivers independently conducted TBFAs on their respective children within the home setting. Fidelity, efficacy, and social validity across each participant were measured. Each caregiver was able to reach fidelity during the training phase, and three out of five caregivers were able to identify a clear behavior function for their child's behavior within the implementation phase of the study. Social validity was evaluated. Results indicate that caregivers may be able to supplement traditional interventionists during the TBFA process. Implications for future practice are reviewed.