Background <p>Health-related quality of life (HRQoL) is increasingly recognized as a critical indicator of well-being in early childhood, yet its associations with 24-hour movement behaviors—physical activity, screen time, and sleep—remain underexplored in Asian populations. This study aims to examine the association between adherence to the 24-hour movement guidelines (24-MG) and health-related quality of life (HRQOL) among preschoolers residing in major urban areas of Singapore, Japan, and China.</p> Methods <p>A cross-sectional survey was conducted among 6,634 children aged 3–6 years across Singapore (<i>n</i> = 3,672), Japan (<i>n</i> = 760), and China (<i>n</i> = 2,202). Movement behaviors were assessed using the validated SMALLQ^® tool, and HRQoL was evaluated using the Pediatric Quality of Life Inventory (PedsQL™). Logistic regression models were applied to determine the associations between different patterns of 24-h MG adherence and HRQoL, adjusting for demographic variables.</p> Results <p>Full adherence to all three 24-h MG components was significantly associated with higher physical and psychosocial HRQoL scores in Singapore and China. In Japan, adherence to physical activity guidelines alone is associated with higher HRQoL. Notably, Chinese children had the highest adherence rates across all individual and combined movement behaviors. Conversely, Japanese children had the lowest rates of full adherence and were more likely to fall short of all guidelines.</p> Conclusions <p>This study provides novel evidence from three urban Asian contexts that adherence to the 24-hour movement guidelines positively correlates with HRQoL in preschool-aged children. The findings highlight the importance of integrated movement behavior frameworks and support the development of culturally tailored public health policies to improve early childhood well-being.</p>