Ubiquinol-cytochrome c reductase core protein 2 (UQCRC2) is an important mitochondrial complex III subunit. This study investigated the role of UQCRC2 in gastric cancer (GC) and its upstream regulatory microRNAs (miRNAs). UQCRC2 expression levels were lower in GC tissues than non-carcinoma tissues. Furthermore, UQCRC2 levels were negatively correlated with lymph node metastasis, relapse, and tumor grade. Bioinformatics analysis predicted UQCRC2 as the target gene for miR-370, and this was verified in luciferase reporter assays. MiR-370 levels were inversely correlated with UQCRC2 levels in GC. UQCRC2 overexpression suppressed GC cell migration and invasion in vitro and in vivo, whereas up-regulating miR-370 reversed these effects. Western blotting analysis showed that miR-370 targeted UQCRC2 and positively regulated the epithelial-mesenchymal transition (EMT) signaling pathway in GC cells. Therefore, the miR-370/UQCRC2 axis may regulate EMT signaling pathways to affect tumor proliferation and metastasis and is, thus, a potential target for GC treatment.