Diabetes mellitus results from high blood glucose levels, requiring better treatment options due to current limitations and side effects. Thus, there's a need to find a safe and effective natural remedy for Type 2 Diabetes Mellitus (T2DM). The research aims to review the literature on the bioactive compounds of Chlorella vulgaris and their involvement in the prevention and treatment of diabetes mellitus. This systematic review was made using the PRISMA guidelines as its basis. The literature research was performed using Science Direct, Taylor & Francis, PubMed, and EBSCOhost databases. This systematic review finding determines that Chlorella vulgaris is a potential natural source that can act as an antidiabetic agent due to its bioactive compounds, such as polyunsaturated fatty acids, peptides, polysaccharides, flavonoids, carotenoids, and carotenoids. The researchers envision the research to encourage further research on Chlorella vulgaris and other microalgae, which will assist in creating important findings in diabetes treatment.