IMPORTANCE: The global incidence of thyroid cancer has been increasing rapidly, and this increase has had an attendant burden on health systems. However, it is unclear how the burden of this disease differs among the pre-2004 countries of the European Union (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, Portugal, Spain, Sweden, and the UK), US, Australia, Canada, and Norway (EU15+). OBJECTIVE: To assess the trends in mortality, incidence, and disability-adjusted life-years (DALYs) associated with thyroid cancer between 1990 and 2019 in EU15+ nations. Data analysis was conducted from July 11 to October 11, 2021. DESIGN, SETTING, AND PARTICIPANTS: Observational cross-sectional analysis of the incidence of thyroid cancer was conducted using data obtained from the Global Burden of Disease Study database. Nineteen countries of the EU15+ were included. EXPOSURES: Thyroid cancer. MAIN OUTCOMES AND MEASURES: Age-standardized incidence rates (ASIRs), age-standardized mortality rates (ASMRs) and DALYs were extracted for individual EU15+ countries per sex for each of the years from 1990 to 2019, and mortality-to-incidence indexes were computed. Joinpoint regression analysis was used to describe the trends. RESULTS: Thirteen of 19 countries (68%) showed an average annual percentage change increase in ASIR across the study period (range, 0.2%-2.5%). Joinpoint regression analysis revealed largely plateauing ASIR trends in recent years across most EU15+ nations since 1990. Between 2011 and 2019, the estimated annual percentage change in the US was 0. Australia, Denmark, and the US were the only countries with increasing ASMR trends with positive average annual percentage changes: Australia, 0.6 (95% CI, 0.2-1.0); Denmark, 1.0 (95% CI, 0.8-1.3); and US, 0.4 (95% CI, 0.4-0.5); the remaining 16 countries showed negative trends (range, -0.2 to -2.1). Disability-adjusted life-years decreased in all EU15+ countries except Australia, Denmark, and the US. CONCLUSIONS AND RELEVANCE: This cross-sectional analysis found that overall, the burden of thyroid cancer across EU15+ countries appears to be decreasing, evidenced by plateauing incidence rates and reductions in mortality and DALYs over the 30-year study period. However, the US and Australia appear to have increasing ASMR and DALY trends. Ongoing observation is required to monitor how changes in international clinical practice guidelines affect thyroid cancer DALYs and mortality.