OBJECTIVE: Non-alcoholic fatty liver disease (NAFLD) is the leading cause of end-stage liver diseases worldwide. Understanding NAFLD prevalence and trends over time at the global, regional and national levels is critical to understanding the NAFLD disease burden and creating more tailored prevention strategies. DESIGN: Population-based observational study. SETTING: The study was global, including 21 regions and 195 countries or territories. MAIN OUTCOMES MEASURE: The estimated annual percentage change for NAFLD prevalence. RESULTS: Worldwide, cases of NAFLD have increased from 391.2 million in 1990 to 882.1 million in 2017, with the prevalence rate increasing from 8.2% to 10.9% during the same period. The increasing trends were consistent across sexes. Case numbers were highest in East Asia, followed by South Asia, then North Africa and the Middle East. The highest prevalence of NAFLD was observed in North Africa and the Middle East, while the greatest increase was detected in Western Europe, followed by Tropical Latin America, then high-income North America. CONCLUSION: Nearly all countries or territories worldwide have experienced a significant increase in NAFLD prevalence. The greatest increase was observed in Oman. Almost all countries showed a significant increasing trend in NAFLD prevalence over the past three decades. This drastic increase is alarming and suggests that NAFLD has emerged as a new public health concern worldwide. As such, more efficient prevention strategies are urgently needed.