Williams syndrome (WS) is a rare congenital anomaly that is characterized by distinctive facial features, congenital heart disease, and behavioral characteristics that include mental retardation. However, only a few reports have documented the dentocraniofacial morphological characteristics of WS in Japanese individuals. The aim of this study was to analyze the dentocraniofacial morphology and growth patterns in a group of nine Japanese subjects (two males and seven females; mean age at admission, 10.1 years) with WS. The analytical methods included an initial medical questionnaire, lateral cephalography, panoramic radiography, dental casts, and oral examinations. The dental findings showed congenitally missing teeth, microdontia, and peg‐shaped teeth. Regarding cranial morphology, microcephaly occurred at high frequencies, and a short posterior cranial base and thick calvarial bones, including frontal, parietal, and occipital bones, were seen in patients with WS. An analysis of maxillofacial morphology showed the large gonial angles and lingual inclination of the lower incisors in patients with WS. In addition, the chin button was deficient and in three of four growing subjects the maxillofacial growth pattern demonstrated a downward and backward tendency. The results of this study provide important information that will improve our understanding of the characteristics of patients with WS.