Smartphone ownership and screen time are increasing across the world, but there have been few attempts to quantify smartphone addiction on a global scale. We conducted a meta-analysis of studies published between 2014 and 2020 that used the Smartphone Addiction Scale, the most common measure of problematic smartphone use. This scale measures whether smartphone use interferes with one’s daily life. We focused on studies of teenagers and young adults (aged 15 to 35) since they show the highest screen time and smartphone ownership rates. Across 85 samples, 24 countries, and 39,292 participants, we demonstrate that problematic smartphone use is increasing across the world. China, Saudi Arabia, and Malaysia had the highest scores while Switzerland, Germany, and France had the lowest. Our results provide global norms for researchers and can help identify countries that could benefit from targeted interventions.