Elucidating the tumorigenic mechanism of R-2-hydroxyglutarate (R-2HG) is critical for determining how NADP⁺-IDH mutations cause cancer. Here we report that R-2HG induces cancerous metabolism and apoptosis resistance through promoting hypersuccinylation. By competitive inhibition of the mitochondrial tricarboxylic acid cycle enzyme succinate dehydrogenase (SDH), R-2HG preferentially induced succinyl-CoA accumulation and hypersuccinylation in the mitochondria. IDH1 mutation-bearing glioma�samples and cells were hypersuccinylated in the mitochondria. IDH1 mutation or SDH�inactivation�resulted in hypersuccinylation, causing respiration inhibition and inducing cancerous metabolism and mitochondrial depolarization. These�mitochondrial dysfunctions induced BCL-2 accumulation at the mitochondrial membrane, leading to apoptosis resistance of hypersuccinylated cells.�Relief of hypersuccinylation by overexpressing the�desuccinylase SIRT5 or supplementing glycine rescued mitochondrial dysfunctions, reversed BCL-2 accumulation, and slowed the oncogenic growth of hypersuccinylated IDH1 ^R132C-harboring HT1080 cells. Thus, R-2HG-induced hypersuccinylation contributes to the tumorigenicity of NADP⁺-IDH mutations, suggesting the potential of hypersuccinylation inhibition as an intervention for hypersuccinylation-related tumors.