Diabetes mellitus (DM) has reached pandemic status and shows no signs of abatement. It can severely impair people’s quality of life and affects patients all over the world. Since it is a serious, chronic metabolic disease, it can bring about many kinds of complications, which can in turn increase mortality. In recent decades, more and more studies have shown that oxidative stress and inflammatory reactions play critical roles in the pathogenesis of DM. There is an increasing demand for natural antidiabetic medicines that do not have the same side effects as modern drugs. Curcumin, a phytochemical found in the spice turmeric, has been used in India for centuries, and it has no known side effects. It has been shown to have some beneficial effects against various chronic illnesses. Many of these therapeutic actions can be attributed to its potent anti-oxidant and anti-inflammatory activities. In view of the oxidative stress and inflammatory mechanisms of DM, curcumin can be considered suitable for the prevention and amelioration of diabetes. In this review, we summarize the nosogenesis of DM, giving primary focus to oxidative stress and inflammation. We discuss the anti-oxidant and anti-inflammatory activities of curcumin in DM and its ability to mitigate the effects on DM and its associated complications in detail.