The strong and positive relationship between gross domestic product (GDP) and health expenditure is one of the most extensively explored topics in health economics. Since the global financial crisis, a variety of theories attempting to explain the slow recovery of the global economy have predicted that future economic growth will be slower than in the past. Others have increasingly questioned whether GDP growth is desirable or sustainable in the long term as evidence grows of humanity's impact on the natural environment. This paper reviews recent data on trends in global GDP growth and health expenditure. It examines a range of theories and scenarios concerning future global GDP growth prospects. It then considers the potential implications for health care systems and health financing policy of these different scenarios. In all cases, a core question concerns whether growth in GDP and/or growth in health expenditure in fact increases human health and well-being. Health care systems in low growth or ‘post-growth’ futures will need to be much more tightly focused on reducing overtreatment and low value care, reducing environmental impact, and on improving technical and allocative efficiency. This will require much more concerted policy and regulatory action to reduce industry rent-seeking behaviours.