The malate–aspartate shuttle is indispensable for the net transfer of cytosolic NADH into mitochondria to maintain a high rate of glycolysis and to support rapid tumor cell growth. The malate–aspartate shuttle is operated by two pairs of enzymes that localize to the mitochondria and cytoplasm, glutamate oxaloacetate transaminases (GOT), and malate dehydrogenases (MDH). Here, we show that mitochondrial GOT2 is acetylated and that deacetylation depends on mitochondrial SIRT3. We have identified that acetylation occurs at three lysine residues, K159, K185, and K404 (3K), and enhances the association between GOT2 and MDH2. The GOT2 acetylation at these three residues promotes the net transfer of cytosolic NADH into mitochondria and changes the mitochondrial NADH/NAD+ redox state to support ATP production. Additionally, GOT2 3K acetylation stimulates NADPH production to suppress ROS and to protect cells from oxidative damage. Moreover, GOT2 3K acetylation promotes pancreatic cell proliferation and tumor growth in vivo. Finally, we show that GOT2 K159 acetylation is increased in human pancreatic tumors, which correlates with reduced SIRT3 expression. Our study uncovers a previously unknown mechanism by which GOT2 acetylation stimulates the malate–aspartate NADH shuttle activity and oxidative protection. Synopsis Acetylation of oxaloacetate transaminase (GOT2) promotes its binding with malate dehydrogenase (MDH2), thereby regulating the malate–aspartate shuttle activity, cytosol‐to‐mitochondrion transfer of NADH, oxidative protection and tumor growth. GOT2 acetylation at three lysine residues enhances its association with MDH2. SIRT3 is the major deacetylase of GOT2. Acetylation of GOT2 modulates mitochondrial NADH/NAD+ redox status, energy production, and cell survival during oxidative stress. GOT2 K159 acetylation is increased in human pancreatic tumors, correlating with reduced SIRT3 expression. Acetylation of oxaloacetate transaminase (GOT2) promotes its binding with malate dehydrogenase (MDH2), thereby regulating the malate–aspartate shuttle activity, cytosol‐to‐mitochondrion transfer of NADH, oxidative protection and tumor growth.