Background: Higher grip strength (GS) is associated with lower mortality risk. However, whether this association is independent of adiposity is uncertain.Objective: The purpose of this study was to examine the associations between GS, adiposity, and mortality.Design: The UK Biobank study is an ongoing prospective cohort of >0.5 million UK adults aged 40-69 y. Baseline data collection (2006-2010) included measurements of GS and adiposity indicators, including body mass index (BMI; in kg/m2). Age- and sex-specific GS quintiles were used. BMI was classified according to clinical cutoffs.Results: Data from 403,199 participants were included in analyses. Over a median 7.0-y of follow-up, 8287 all-cause deaths occurred. The highest GS quintile had 32% (95% CI: 26%, 38%) and 25% (95% CI: 16%, 33%) lower all-cause mortality risks for men and women, respectively, compared with the lowest GS quintile, after adjustment for confounders and BMI. Obesity class II (BMI ≥35) was associated with a greater all-cause mortality risk. The highest GS quintile and obesity class II category showed relatively higher all-cause mortality hazards (not statistically significant in men) than the highest GS quintile and the normal weight category; however, the increased risk was relatively lower than the risk for the lowest GS quintile and obesity class II category. All-cause mortality risks were generally lower for obese but stronger individuals than for nonobese but weaker individuals. Similar patterns of associations were observed for cardiovascular mortality.Conclusions: Lower grip strength and excess adiposity are both independent predictors of higher mortality risk. The higher mortality risk associated with excess adiposity is attenuated, although not completely attenuated, by greater GS. Interventions and policies should focus on improving the muscular strength of the population regardless of their degree of adiposity.