The invention provides herein engineered regulatory T cells (Tregs), compositions thereof, and their methods of use. The Tregs described herein can be engineered to include, e.g., a chimeric antigen receptor (CAR), conferring increased stability, specificity, and immunosuppressive activity towards a target antigen. Furthermore, Tregs can also be engineered to reduce T cell cytotoxicity functions. Also provided are methods of suppressing immune response against a specific target antigen using the engineered Tregs described herein.