Objectives: This study aimed to compare the utility of the Psychoeducational Profile-Revised (PEP-R), Korean Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (K-WPPSI-IV), and Vineland Adaptive Behavior Scale, Second Edition (VABS-II) for evaluating developmental disabilities (DD) in preschool children. Additionally, we examined the correlations between the PEP-R, KWPPSI-IV, and VABS-II. Methods: A total of 164 children aged 37–84 months were assessed. Children’s development was evaluated using the PEP-R, K-WPPSIIV, VABS-II, Preschool Receptive-Expressive Language Scale, and Korean Childhood Autism Rating Scale, Second Edition. Results: Of the 164 children, 103 had typical development (TD) and 61 had DD. The mean of the PEP-R Developmental Quotient (DQ), K-WPPSI-IV Full-Scale Intelligence Quotient (FSIQ), and VABS-II Adaptive Behavior Composite (ABC) scores were significantly higher in the TD group than in the DD group (p<0.001). The estimated area under the curve of the PEP-R DQ, K-WPPSI-IV FSIQ, and VABS-II ABC scores was 0.953 (95% confidence interval [CI]=0.915–0.992), 0.955 (95% CI=0.914–0.996), and 0.961 (95% CI=0.932– 0.991), respectively, which did not indicate a statistically significant difference. The PEP-R DQ scores were positively correlated with the K-WPPSI-IV FSIQ (r=0.90, p<0.001) and VABS-II ABC scores (r=0.84, p<0.001). A strong correlation was observed between the KWPPSI-IV FSIQ and VABS-II ABC scores (r=0.89, p<0.001). Conclusion This study found that the PEP-R, K-WPPSI-IV, and VABS-II effectively distinguished DD from TD in preschool children, and no significant differences in utility were observed between them.