There is an equivocal and inconsistent association between legume consumption and health outcomes and longevity. The purpose of this study was to examine and quantify the potential dose–response relationship between legume consumption and all-cause and cause-specific mortality in the general population. We conducted a systematic literature search on PubMed/Medline, Scopus, ISI Web of Science, and Embase from inception to September 2022, as well as reference lists of relevant original papers and key journals. A random-effects model was used to calculate summary HRs and their 95% CIs for the highest and lowest categories, as well as for a 50 g/d increment. We also modeled curvilinear associations using a 1-stage linear mixed-effects meta-analysis. Thirty-two cohorts (31 publications) involving 1,141,793 participants and 93,373 deaths from all causes were included. Higher intakes of legumes, compared with lower intakes, were associated with a reduced risk of mortality from all causes (HR: 0.94; 95% CI: 0.91, 0.98; n = 27) and stroke (HR: 0.91; 95% CI: 0.84, 0.99; n = 5). There was no significant association for CVD mortality (HR: 0.99; 95% CI: 0.91, 1.09; n =11), CHD mortality (HR: 0.93; 95% CI: 0.78, 1.09; n = 5), or cancer mortality (HR: 0.85; 95% CI: 0.72, 1.01; n = 5). In the linear dose–response analysis, a 50 g/d increase in legume intake was associated with a 6% reduction in the risk of all-cause mortality (HR: 0.94; 95% CI: 0.89, 0.99; n = 19), but no significant association was observed for the remaining outcomes. The certainty of evidence was judged from low to moderate. A higher legume intake was associated with lower mortality from all causes and stroke, but no association was observed for CVD, CHD, and cancer mortality. These results support dietary recommendations to increase the consumption of legumes.