Diabetes mellitus is a widespread metabolic disorder marked by chronic hyperglycemia due to defects in insulin secretion, insulin action, or both. The incidence of diabetes mellitus is rising at an alarming rate. Type 2 diabetes mellitus, in particular, is driven by lifestyle factors and genetic predispositions. Management strategies emphasize lifestyle modifications, including diet and exercise, as well as pharmacological treatments. Recently, the potential of functional foods and natural supplements, such as Spirulina, has garnered significant interest. Spirulina, a nutrient-dense cyanobacterium, has been consumed for centuries as it is high in protein and vitamin. It exhibits multiple health benefits, including immune modulation and anti-inflammatory properties. Recent studies have explored Spirulina's potential in managing diabetes mellitus. Spirulina’s bioactive compounds, such as phycocyanin, and gamma-linolenic acid, contribute to these therapeutic effects. Additionally, Spirulina may aid in weight loss and mitigate diabetes-related complications, such as neuropathy, nephropathy, and cardiovascular disease. This review highlights the historical use, nutritional profile, and emerging evidence on Spirulina's role in diabetes mellitus management. It discusses how Spirulina can be incorporated into the diet and emphasizes precautions for its use. While promising, Spirulina should complement rather than replace conventional diabetes mellitus treatments. Further research is necessary to fully understand its mechanisms and long-term benefits in diabetes mellitus management.