Lower respiratory infections (LRIs) are a leading cause of death worldwide. We aimed to estimate the trends of global and regional aetiologies, risk factors and mortality of LRIs from 1990 to 2019. From the Global Burden of Disease (GBD) Study 2019, we collected relevant data, including annual LRI deaths, mortality and deaths and mortality attributable to the four high-burden aetiologies and 14 risk factors during 1990-2019. To quantify the temporal trends, estimated annual percentage changes (EAPCs) were calculated by fitting linear regression model. Globally, the age-standardized mortality due to LRIs decreased by an average of 2.39% (95% CI 2.33%-2.45%) per year, from 66.67 deaths per 100,000 in 1990 to 35.72 deaths per 100,000 in 2019. Low Socio-demographic Index regions, South Asia and Sub-Saharan Africa had the heaviest burden of LRIs. The age-standardized mortality decreased in 18 GBD regions, whereas increased in Southern Latin America (EAPC = 1.20, 95% CI 1.03-1.37). LRIs led to considerable deaths among children under 5 years and adults older than 70 years. Streptococcus pneumoniae was the first leading aetiology, accounting for over 50% of LRI deaths. Household air pollution from solid fuels, child wasting and ambient particulate matter pollution were the three leading risk factors for LRI mortality in 2019. LRIs remain an important health problem globally, especially in some vulnerable areas and among children under 5 and adults over 70 years. Future researches focusing on the aetiologies and risk factors for LRIs are needed to provide targeted and updated prevention strategies.