The present study sought to examine the relationships between two language assessments and a psychometrically validated adaptive behavior scale. The assessments evaluated included the Promoting the Emergence of Advanced Knowledge Relational Training System - Direct Training Module (PEAK-DT), the Assessment of Basic Language and Learning Skills - Revised (ABLLS-R), and the Vineland Adaptive Behavior Scales, second edition (VABS-II). The assessments were completed for 21 children diagnosed with autism. Results indicate a significant correlation between scores on the PEAK-DT and ABLLS-R (r = 0.951, p < 0.001, PEAK-DT and VABS-II (r = 0.453, p < .05), as well as the ABLLS-R and VABS-II (r = 0.563, p < 0.05). The results did not indicate any ceiling effects amongst any of the assessments. These results extend research on the psychometric properties of these assessment tools and provide implications for practitioner choice of curricula.