Evasion of apoptosis is one of the typical hallmarks of cancer and a major mechanism for cancer development, tumor growth, and acquisition of resistance to chemotherapy. The anti-apoptotic Bcl-2 protein family, particularly MCL1 and BCL-XL, play an important role in acquisition of apoptosis evasion. MCL1 is a highly unstable protein that is constantly degraded by the ubiquitinproteasome system. An increase in MCL1 protein has been reported in many cancers, including lung cancer, through high mRNA expression or impairment of its degradation systems. To date, much evidence has shown that MCL1 is important for cancer cell survival and drug resistance in lung cancers. In this review, we discuss the role and mechanism of high MCL1 expression in lung cancer.