Meat by-products and co-products, including poultry and fish wastes, represent a current challenge for the food processing industry due to their harmful impact on the environment. Membrane technologies, thanks to their intrinsic properties, represent an emerging tool for the valorization of these streams according to the principles of a sustainable circular economy. A review of significant applications of membrane-based technologies, including pressure-driven membrane processes and electro-membrane processes, for the recovery of protein-based compounds from meat by-products is presented along with their trends and future potentials in the production of functional ingredients. Classic and recent development works are analyzed and critically discussed according to the relevant results in the field. Literature data clearly indicate that membrane technologies represent an efficient and environmentally friendly option for the separation, fractionation, and purification of bioactive compounds from different meat co-products. The implementation of such processes as a way of recovering biomolecules also gives environmental benefits by reducing the organic load of both by-and co-products.