Abstract Background The obesogenic quality of the home environment is hypothesised to play an important role in children’s weight development but few prospective studies have investigated relationships between the home environment and adiposity across childhood. Objective To investigate the continuity and stability of the home environment from ages 4 to 12, and bi-directional relationships between the home environment and BMI-SDS from ages 4 to 12. Methods Parents from the Gemini cohort completed the Home Environment Interview (HEI), a comprehensive measure of the obesogenic home environment, when their children were aged 4 and 12 (n = 149 families, n = 298 children). The obesogenic home environment was measured using four composite scores capturing the food, activity, media environments, and the overall home environment. Child weights and heights were used to calculate BMI-SDS. Continuity was assessed with Pearson’s correlations between scores at each time point, and stability by changes in mean scores over time. Cross-lagged analyses were performed (HEI composites at age 4 to BMI-SDS at age 12 and the reverse) to measure the magnitude and direction of associations. Results The home environment showed moderate-to-high continuity from ages 4 to 12 (r = 0.30–0.64). The overall home environment (r = 0.21, p < 0.01) and media composites (r = 0.23, p < 0.01) were cross-sectionally associated with child BMI-SDS at age 12, but not at age 4. Longitudinally, the home media environment at age 4 predicted increases in child BMI-SDS at age 12 (β; 95% CI = 0.18; 0.08,0.28, p < 0.01). No associations were observed for the reverse path, or the remaining composites (the overall, food and activity) in either direction. Conclusion This study provides evidence that the obesogenic home environment tracks across childhood and highlights the importance of the early home media environment for child weight development. The findings provide insight into key aspects of the home environment that could be targeted when developing obesity treatment or prevention strategies.