More than 80% of psychologists report using alternative assessment measures in place of, or to supplement, traditional standardized assessments to evaluate young children for special education eligibility, placement, and services. Recent research indicates that nearly 97% of alternative assessment tools currently used by psychologists and trained early interventionists to assess special education eligibility in early childhood are play-based measures that aim to provide an ecologically valid picture of a child’s functioning across settings and to help inform specific interventions for treatment planning. However, limited research exists on the psychometric properties of play-based assessment measures for use in early childhood. In addition, psychologists are increasingly seeking strengths-based assessment tools to identify social-emotional concerns and protective factors for children in early childhood in an effort to provide a more comprehensive picture of the child’s everyday functioning. In consideration of the research that social-emotional health and adaptive delays for ages 3 and younger may directly influence later functional outcomes for children, this paper explores the current practices and rationale for adjunctive and alternative approaches to assessment in early childhood. This study investigated the validity of scores obtained from a play-based assessment tool, the Transdisciplinary Play-Based Assessment, Second Edition (TPBA-2; Linder, 2008). Findings from this study serve to provide additional psychometric support for the use of play-based assessments, especially for children with suspected developmental disabilities or delays in early childhood. Specifically, this study examined the concurrent validity between (N = 44) children’s social-emotional functioning as assessed by the TPBA-2 and The Devereux Early Childhood Assessment-Clinical Form (DECA-C; LeBuffe & Naglieri, 2012). Results indicated significant (p < .001) associations between the measures. In addition, the study found evidence of social validity for the TPBA-2 as rated by the assessment team members (N = 41) and caregivers (N = 12). These findings provide additional evidence of concurrent and social validity in support of the TPBA-2 as an evaluation tool for the assessment of young children for early intervention and special education services.