Early intervention and early childhood special education professionals espouse the need for authentic assessment and meaningful family involvement, as well as relationship-based and routines-based intervention. This article explores a play-based approach to assessment that reflects these values by using the Transdisciplinary Play-Based Assessment, Second Edition (TPBA2). The authors describe the theoretical underpinnings and research findings of the TPBA2 and compare it with other common assessment tools, including the Bayley Scales of Infant Development-Third Edition, the Mullen Scales of Early Learning, and the Vineland Adaptive Behavior Scales.