Background <p>Cisplatin (DDP) is often used as a treatment option for metastatic non-small cell lung cancer (NSCLC). However, DDP resistance is a substantial obstacle to effective therapy. In this study, the roles and mechanisms of ubiquitin-specific peptidase 7 (USP7) and B-cell lymphoma-2 (BCL2) in DDP resistance of NSCLC were explored.</p> Methods <p>qRT-PCR, western blot and IHC assays were performed for the detection of gene expression. DDP resistance and cell viability were estimated by MTT assay. Cell proliferation, apoptosis, invasion and stemness were explored by EdU assay, flow cytometry analysis, transwell assay and sphere formation assay, respectively. The relation between USP7 and BCL2 was analyzed by ubiquitination assay and immunofluorescence colocalization assay. Murine xenograft model was established to explore the function of BCL2 in DDP resistance in vivo.</p> Results <p>BCL2 was highly expressed in DDP-resistant NSCLC tissues and cells. Silencing of BCL2 restrained DDP resistance, cell proliferation, invasion and stemness and facilitated apoptosis in DDP-resistant NSCLC cells. Mechanistically, USP7 regulated BCL2 expression through the deubiquitination of BCL2. USP7 knockdown repressed DDP resistance and the malignant behaviors of DDP-resistant NSCLC cells, with BCL2 overexpression restored the effects. Furthermore, BCL2 knockdown curbed DDP resistance in vivo.</p> Conclusion <p>USP7 promoted DDP resistance, cell growth, invasion and stemness in DDP-resistant NSCLC cells by regulating BCL2 expression.</p> Graphical abstract <p></p>