The current set of experiments examined the utility of implementing the Promoting the Emergence of Advanced Knowledge (PEAK) Relational Training System (Dixon, 2014a, 2014b), an empirically validated assessment and intervention guide developed for children diagnosed with autism spectrum disorder (ASD), within Intensive Behavioral Intervention (IBI). Experiment 1 examined the relationship between scores on the commonly used Vineland Adaptive Behavior Scales Second Edition (VABS-II) (Sparrow, Cicchetto, & Balla, 2005) and scores on the PEAK Direct Training (PEAK-DT) (Dixon, 2014a) and PEAK Generalization (PEAK-G) (Dixon, 2014b) program assessments to examine additional psychometric properties suggesting the potential utility for use within IBI services. Experiment 2 examined the extent to which the PEAK manual (Dixon, 2014b) or additional staff training increased PEAK discrete trial training (DTT) procedural integrity of staff providing IBI to children diagnosed with ASD. Experiment 3 examined the effects of PEAK-G curriculum and instruction on the advanced language skills of children with ASD receiving IBI services. Results suggest that PEAK may be a valid assessment tool and effective intervention guide for use in IBI. Also, the manual and other effective staff training procedures (e.g., feedback, behavioral skills training) effectively enhance PEAK-G DTT procedural integrity. Lastly, the set of experiments in the current paper contributes to the dissemination of empirically based, behavior-analytic research that contributes to practical assessments and advanced interventions for children diagnosed with ASD. Specifically, PEAK-G enhances the language repertoires of children diagnosed with ASD through direct contingencies and programming for generalization across generalization gradients.