This study investigates the relationship between population dynamics and economic growth in India and China over the period 1960 to 2023, focusing on major demographic indicators such as population growth, birth rates, working-age population share, elderly population proportion, and age dependency ratios. Using pooled OLS regression analysis, the research evaluates how demographic transitions have influenced economic outcomes in the two fastest-growing Asian economies. The findings indicate that an expanding working-age population has played a crucial role in accelerating GDP growth, particularly in India, where the demographic dividend continues to provide economic advantages. In contrast, China’s early demographic transition, shaped significantly by its one-child policy, has led to a rapidly ageing population, rising dependency burdens, and emerging labour shortages. These demographic shifts pose long-term challenges for sustaining growth. The study highlights that investments in education, healthcare, and skill development are essential to maximise the benefits of demographic changes. It further suggests that India can learn valuable lessons from China’s experience in managing demographic transitions to ensure sustainable development. Overall, this comparative analysis offers important insights for policymakers aiming to align population trends with long-term economic planning and achieve balanced, inclusive growth in both countries.