Research Findings: This study investigated the relationship between the use of digital devices (DD) by preschool children in Hong Kong and their early development. The moderating role of family socioeconomic status (SES) was also examined. A total of 877 Chinese Hong Kong children aged 3-5 years old from 18 kindergartens and their parents participated in this study. The parents reported their children's DD use, including whether they used DD, the daily time spent using DD, what they used DD for, and the situations in which they used DD. The Hong Kong Early Child Development Scales and Movement Assessment Battery for Children were used to understand these children's development in various domains. The results showed that 74.54% of the children had experience using DD. Use of DD and time spent using DD were found to negatively predict children's performance on General Knowledge, Fine Motor Skills, and Gross Motor Skills. Watching cartoons was found to negatively predict children's performance on Early Academic Achievement, General Knowledge, and Fine Motor Skills. Children's DD use before bedtime or on request also had a negative relationship with their performance on Fine Motor Skills. Moreover, SES had a significant moderating effect on the relationship between children's use of DD before bed and their performance on General Knowledge. Practice or Policy: These findings suggest that parents reduce the time and frequency of their children's DD use, monitor their DD activities, and prevent them from using DD before bedtime.