Insulin is a major regulator of glucose metabolism, stimulating its mitochondrial oxidation in skeletal muscle. Mitochondria are dynamic organelles that can undergo structural remodeling in order to cope with these ever-changing metabolic demands. However, how mitochondrial morphology impacts insulin signaling in the skeletal muscle is far from being completely elucidated. To address this, we silenced two mitochondrial fusion proteins, Mfn2 and Opa1, and assessed insulin response in L6 rat skeletal muscle cells. We found that mitochondrial fragmentation attenuates insulin-stimulated Akt phosphorylation, glucose uptake, and respiratory rate. Insulin is a major regulator of glucose metabolism, stimulating its mitochondrial oxidation in skeletal muscle cells. Mitochondria are dynamic organelles that can undergo structural remodeling in order to cope with these ever-changing metabolic demands. However, the process by which mitochondrial morphology impacts insulin signaling in the skeletal muscle cells remains uncertain. To address this question, we silenced the mitochondrial fusion proteins Mfn2 and Opa1 and assessed insulin-dependent responses in L6 rat skeletal muscle cells. We found that mitochondrial fragmentation attenuates insulin-stimulated Akt phosphorylation, glucose uptake, and cell respiratory rate. Importantly, we found that insulin induces a transient raise in mitochondrial Ca²⁺ uptake, which was attenuated by silencing Opa1 or Mfn2. Moreover, treatment with Ruthenium Red, an inhibitor of mitochondrial Ca²⁺ uptake, impairs Akt signaling without affecting mitochondrial dynamics. Altogether, these results suggest that control of mitochondrial Ca²⁺ uptake by mitochondrial morphology is a key event for insulin-induced glucose uptake.