Cancer remains a global health challenge, driving the need for advanced treatments. While transition metal dichalcogenides (TMDs) show promise in cancer therapy, their stability and efficacy require improvement. This study explores TMD-based composites as a solution to enhance their therapeutic potential. This review begins by providing an overview of TMDs and emphasizing their preparation techniques and fundamental properties. The focus is then shifted to categorizing TMD-based composites based on their constituent materials, delving into various types, such as TMD-organic, TMD-carbon, TMD-metal chalcogenide, TMD-metal, and TMD-oxide composites, as well as more complex ternary and multinary systems. We further explore key fabrication strategies, including hydrothermal/solvothermal methods and surface deposition/coating techniques. Subsequently, the focus shifted to their applications in cancer treatment, including chemotherapy, photothermal therapy, phototherapy, and integrated combination therapies. Finally, critical challenges in the field and perspectives on potential directions for future research are presented.