Due to rapid global urbanization and changes in population lifestyles, diabetes mellitus is currently the third leading cause of death on the planet. This metabolic disorder is characterized by hyperglycemia, resulting from insufficient insulin secretion or an inadequate response by the body to its action. In this sense, the growing demand for natural products has attracted the interest of the pharmaceutical industry in microalgae. These photosynthetic microorganisms stand out for the vast diversity of bioactive compounds capable of improving insulin sensitivity, attributed to their antioxidant and anti-inflammatory properties. However, further research on the action of these microalgal metabolites is needed for their full exploration and effective pharmaceutical and industrial applications. In this context, this chapter aims to provide a more comprehensive view of the diversity of microalgal biocompounds applicable in the prevention of this metabolic disorder, including (i) aspects related to the overall risk of the disease; (ii) microalgal biocompounds and mechanisms associated with antidiabetic effects; (iii) related scientific evidence, as well as (iv) future perspectives and existing challenges.