Background The relationship between lowering LDL (low-density lipoprotein) cholesterol with contemporary lipid-lowering therapies and incident diabetes mellitus ( DM ) remains uncertain. Methods and Results Thirty-three randomized controlled trials (21 of statins, 12 of PCSK9 [proprotein convertase subtilisin/kexin type 9] inhibitors, and 0 of ezetimibe) were selected using Medline , Embase, and the Cochrane Central Register of Controlled Trials (inception through November 15, 2018). A total of 163 688 nondiabetic patients were randomly assigned to more intensive (83 123 patients) or less intensive (80 565 patients) lipid-lowering therapy. More intensive lipid-lowering therapy was defined as the more potent pharmacological strategy ( PCSK 9 inhibitors, higher intensity statins, or statins), whereas less intensive therapy corresponded to active control group or placebo/usual care of the trial. Metaregression and meta-analyses were conducted using a random-effects model. No significant association was noted between 1-mmol/L reduction in LDL cholesterol and incident DM for more intensive lipid-lowering therapy (risk ratio: 0.95; 95% CI , 0.87-1.04; P=0.30; R=14%) or for statins or PCSK 9 inhibitors. More intensive lipid-lowering therapy was associated with a higher risk of incident DM compared with less intensive therapy (risk ratio: 1.07; 95% CI , 1.03-1.11; P<0.001; I=0%). These results were driven by higher risk of incident DM with statins (risk ratio: 1.10; 95% CI , 1.05-1.15; P<0.001; I=0%), whereas PCSK 9 inhibitors were not associated with incident DM (risk ratio: 1.00; 95% CI , 0.93-1.07; P=0.96; I=0%; P=0.02 for interaction). Conclusions Among intensive lipid-lowering therapies, there was no independent association between reduction in LDL cholesterol and incident DM . The risk of incident DM was higher with statins, whereas PCSK 9 inhibitors had no association with risk of incident DM .