Abstract: Half-Heuslers thermoelectric materials are potential candidates for medium-to-high temperature waste heat recovery, owing to their good thermal stability and mechanical strength. In this particular material system, the ZTs of both p-type and n-type half-Heuslers have improved gradually in recent years and its peaks have exceeded 1.0. This review serves as a guide to learn the recent progress in half-Heuslers system: including the application of nanocomposite approach, enhanced alloy scattering by larger atomic and size differences and the exploration of ternary systems as well as new classes of materials. Though the ZTs of half-Heuslers have surpassed 1.0, the cost is still high. Therefore, reducing the cost and optimizing the performance of the new half-Heuslers materials will be the major study in the future. At present, enhancing the ZTs also has much potential. The average gain size of samples after hot pressing is more than 100 nm. So the further improvement of ZT will be realized by reducing the larger gain size. Meanwhile, the usage of energy filtering effect in half-Heuslers is expected to boost its thermoelectric properties.