Objectives: Ketamine has a fast onset of action that may offer a paradigm change for depression management at the end of life. We aimed to synthesize evidence regarding the safety and efficacy of ketamine in depression treatment within a broad palliative care concept. Methods: We searched seven databases and included studies on the safety and efficacy of ketamine for depression treatment in patients diagnosed with any life-threatening disease. We also conducted a narrative review of the evidence. Results: Among 2,252 screened titles and abstracts, we included 32 studies in our final synthesis: 14 case reports, two case series, two quasi-experimental studies, and seven randomized clinical trials (RCTs), as well as data from three unpublished clinical trials and seven cases from four larger case series. Most case reports reported a robust effect; however, the larger studies reported conflicting findings. Five RCTs reported positive outcomes; however, four of them were focused on a perioperative setting. Two negative studies did not primarily focus on depression and did not apply severity cutoffs. Conclusion: Although ketamine is generally safe and potentially useful, its efficacy in palliative care settings remains unclear. It may be a reasonable alternative for perioperative depression in oncological patients.