Objective To analyze and compare the disease burden, trends, and influencing factors of lung cancer in adolescents and young adults (AYAs) in China and globally from 1990 to 2021, providing a reference for the prevention and treatment of lung cancer in China. Methods Indicators of lung cancer disease burden in different genders and age groups in 204 countries or regions from 1990 to 2021 were retrieved and standardized from GBD 2021 database. The Joinpoint regression model was used to calculate the average annual percentage change (AAPC) of the standardized rates of lung cancer in AYAs in China and globally from 1990 to 2021; changes in incidence, mortality, and disability-adjusted life years (DALYs) rates due to population growth, aging, and epidemiological changes were analyzed; differences in lung cancer disease burden in AYAs in different socio-demographic index (SDI) regions were analyzed; and the influencing factors of lung cancer in AYAs in China and globally were explored. Results From 1990 to 2021, the age-standardized incidence rate (ASIR) (AAPC=−0.18%, P<0.001), age-standardized mortality rate (ASMR) (AAPC=−0.62%, P<0.001), and age-standardized DALYs rate (AAPC=−0.62%, P<0.001) of lung cancer in AYAs in China showed a downward trend, consistent with the global trend, but the decline in China was relatively small. During this period, the age-standardized rates of various indicators of lung cancer in males in China and globally were higher than those in females, and the burden of lung cancer in Chinese males was heavier. However, due to the significant downward trend in males, the gap in lung cancer burden between males and females was narrowing. At the same time, from 2013 to 2021, the ASIR [annual percent change (APC)=2.01%, P<0.001], ASMR (APC=1.46%, P<0.001), and standardized DALYs rate (APC=1.46%, P<0.001) in China showed an upward trend. From 1990 to 2021, among the main influencing factors for the incidence, mortality, and DALYs rates of lung cancer in Chinese AYAs, the contribution of aging was upward-pushing, while the increase in global indicators was mainly attributed to population growth. The global burden of lung cancer in AYAs was overly concentrated in high SDI regions. Although the gap in lung cancer burden between high SDI and low SDI regions was narrowing, it remained widespread. Globally, smoking, environmental PM2.5, insufficient fruit intake, second-hand smoke, and indoor air pollution were prominent risk factors. Conclusion From 1990 to 2021, the global and Chinese AYAs lung cancer incidence and mortality rates generally show a downward trend, but the female lung cancer burden relatively increases, especially in young women without a history of smoking. Continued efforts are needed to reduce the burden of lung cancer in AYAs, especially the specific risk for young women.