Metabolic diseases represent a wide category of alterations affecting metabolism. These pathologies are notably marked by inflammation that implicates the immune system. Mucosal Associated Invariant (MAI)T cells are immune cells expressing a semi-invariant TCR able to recognize bacterial and fungal vitamin B metabolites. MAIT cells can promote inflammation and are present in many organs central to metabolism, suggesting a role in the etiopathology of these diseases. SCOPE OF THE REVIEW: Here, we will review what is known of the involvement of MAIT cells in metabolic pathologies in humans and mice. MAJOR CONCLUSIONS: MAIT cells are severely affected, overactivated with a frequency reduction and a phenotype shift from protective to deleterious. Therefore, they might be a novel target to treat, in particular, pancreas and liver metabolic diseases.