INTRODUCTION Smoking is a significant risk factor for prostate cancer (PCa), a major health threat for aging males globally. This study evaluates the worldwide burden of smoking-related PCa from 1990 to 2021 and projects trends to 2031. METHODS Using Global Burden of Disease (GBD) 2021 data, we analyzed age-standardized rates (ASRs) and estimated annual percentage changes for mortality, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life years (DALYs) across different age groups, sociodemographic index (SDI) levels, regions, and countries, employing hierarchical clustering and autoregressive integrated moving average (ARIMA) modeling. RESULTS From 1990 to 2021, global smoking-related prostate cancer burden declined, with annual reductions in ASRs for mortality, YLLs, and DALYs, while YLDs initially increased before declining. Age-specific analysis revealed the highest ASRs for mortality, YLLs, and DALYs in the 90-94 years age group, whereas YLDs peaked at 70-74 years of age. SDI regions exhibited elevated ASRs but the most pronounced declines, and were the only areas with negative YLD trends. The disparity in disability rates between high and low SDI countries diminished from 7.33 (95% CI: 6.04-8.63) in 1990 to 3.78 (95% CI: 2.64-4.92) in 2021, and the concentration index decreased from 0.34 (95% CI: 0.28-0.39) to 0.15 (95% CI: 0.10-0.20). The ARIMA models predict that DALYs will decrease from 3.215 (95% CI: 3.169-3.26) in 2022 to 2.69 (95% CI: 2.159-3.221) in 2031, YLLS will decrease from 2.827 (95% CI: 2.787-2.866) to 2.336 (95% CI: 1.855-2.817), YLDs and deaths will stabilize in a gradually decreasing trend. CONCLUSIONS Despite improved global equity in smoking-related PCa burden, targeted interventions for elderly populations, enhanced tobacco control policies, and region-specific prevention strategies remain essential to further reduce this preventable disease burden worldwide.