Background <p>The home-rearing environment plays a key role in early childhood development, particularly in gross motor development. However, evidence from non-Western contexts, including Japan, remains limited.</p> Objective <p>This study aimed to identify patterns of home-rearing environment and examine their associations with children’s gross motor development in Japan.</p> Methods <p>Using two-year longitudinal data from the “Child Care Cohort Study,” 935 children aged 0–6 years were analyzed. Caregivers completed questionnaires assessing multiple dimensions of the home-rearing environment, and trained professionals assessed children’s gross motor development using the Child Development Scale. Latent profile analysis was conducted to identify subtypes of the home-rearing environment.</p> Results <p>Three home-rearing environment profiles were identified: low social support, relative restriction, and high overall support. The association between low social support and atypical gross motor development varied depending on contextual factors, particularly child age and family structure. Notably, the association became stronger as children grew older.</p> Conclusions <p>These findings underscore the heterogeneity of home-rearing environments and their relevance to children’s gross motor development. The results highlight the importance of considering contextual factors when examining developmental outcomes and indicate that children in low social support environments may require additional support.</p>