Diabetes is a chronic metabolic disorder. Diabetes complications can affect many organs and systems in the body. Ganoderma lucidum (G. lucidum) contains various compounds that have been studied for their potential antidiabetic effects, including polysaccharides, triterpenoids (ganoderic acids, ganoderol B), proteoglycans, and G. lucidum extracts. G. lucidum polysaccharides (GLPs) and triterpenoids have been shown to act through distinct mechanisms, such as improving glucose metabolism, modulating the mitogen-activated protein kinase (MAPK) system, inhibiting the nuclear factor-kappa B (NF-κB) pathway, and protecting the pancreatic beta cells. While GLPs exhibit a significant role in controlling diabetic nephropathy and other associated complications. This review states the G. lucidum antidiabetic mechanisms of action and potential biologically active compounds that contribute to diabetes management and associated complications. To make G. lucidum an appropriate replacement for the treatment of diabetes with fewer side effects, more study is required to completely comprehend the number of physiologically active compounds present in it as well as the underlying cellular mechanisms that influence their effects on diabetes.