Currently, cancer is one of the leading causes of death in the world, with an estimated 28.4 million cases in 2040. Cancer treatment depends on the type, severity, and stage of the cancer and includes: Chemotherapy, surgery, radiotherapy, hormone therapy, anti-angiogenic therapies, stem cell therapies, and targeted therapies, which include immunotherapy. However, one of the disadvantages of these therapies is that they do not selectively eliminate cancer cells, meaning that healthy cells are also damaged. Recently, nanotechnology has provided an alternative for the development of new cancer therapies, as nanomaterials can offer greater specificity compared to current treatments without causing the adverse effects of conventional therapies. In particular, nanoparticles made of noble metals (silver, gold, and platinum) may be promising candidates for cancer therapy, as their physical and chemical properties allow them to exert a cytotoxic mechanism through several mechanisms of action, such as the generation of reactive oxygen species (ROS), which leads to oxidative stress, DNA damage, cell cycle arrest, apoptotic/necrotic cell death, and autophagy. On the other hand, photothermal therapy uses the heat generated by the conversion of photon energy with the aim of selectively killing cancer cells. This therapy with nanomaterials can be an alternative treatment against cancer, mainly due to the antitumor properties that noble metal nanoparticles have through the different mechanisms of action they exert on cancer. This chapter, through a systematic and specialized search, aims to provide a current under-standing of the role of noble metal nanomaterials in cancer therapy.