Among B-cell lymphoma, multiple myeloma (MM) is an incurable malignancy. miR-140-3p was known to be an inhibitor in malignant tumors. However, the function of miR-140-3p in MM remains unclear. qRT-PCR was performed to determine the expressions of miR-140-3p and BZW2 mRNA. The protein level of BZW2 was determined by the western blot. Cell viability or cell apoptosis was detected by the MTT assay or flow cytometry, respectively. Binding between miR-140-3p and BZW2 was validated using the dual luciferase assay. Xenograft model was applied to verify the results of in vitro study. The level of miR-140-3p was significantly downregulated in MM. Overpexression of miR-140-3p impaired the proliferation of MM cell lines and induced apoptosis in MM cells. miR-140-3p was validated to target BZW2 and inhibit the expression of BZW2. BZW2 was involved in the regulation of miR-140-3p on MM cell vitality and apoptosis. In vivo study revealed that miR-140-3p impeded tumorigenesis of MM cell line in nude mice. Our present study revealed that miR-140-3p served as a suppressor in MM by negatively regulating BZW2. Thus, miR-140-3p could act as a new target for treating MM.