The aim of this study was to develop and validate the Childhood Nonverbal Communication Scale (CNCS) to assess nonverbal communication skills in children from birth to 18 months old. An extensive review of existing research provided evidence used to generate items representative of nonverbal communication behaviors. The final version of the CNCS includes 37 items divided in two dimensions (CNCS-1 and CNCS-2) showing high content validity (item-rated content validity index ≥ 0.75). The scale was administered to 428 Iranian Persian-speaking children 3 to 18 months old with normal development. According to the findings, the CNCS showed strong internal consistency (KR-20 = 0.965). Further, it had good convergent validity based on a significant correlation between total scores and the results of the Persian version of the Production of Infant Scale Evaluation (PRISE-P) (r = 0.5, P < 0.01). Therefore, the CNCS is a promising tool for measuring nonverbal communication in Iranian children from birth to 18 months of age.