This review summarizes recent advances in the development of high-performance thermoelectric (TE) materials with a high dimensionless figure of merit (ZT). Thermoelectric materials convert thermal energy directly into electrical energy and are used for power generation and refrigeration. Over the past decade, significant progress has been made in improving the ZT of TE materials through nanostructuring, which allows for better control of thermoelectric parameters such as electrical conductivity, Seebeck coefficient, and thermal conductivity. Nanostructures enable the decoupling of thermal and electrical transport by introducing new scattering mechanisms, leading to enhanced TE performance. The review discusses various high-ZT materials, including Bi–Te alloys, skutterudite compounds, Ag–Pb–Sb–Te quaternary systems, half-Heusler compounds, and high-ZT oxides. Strategies for improving TE performance include reducing lattice thermal conductivity through nanostructural design, optimizing the power factor, and enhancing the Seebeck coefficient. The review also highlights the importance of nanostructuring in achieving high ZT values and discusses future directions for improving TE materials. Key findings include the use of nanostructures to reduce thermal conductivity, the role of grain boundaries and interfaces in enhancing TE performance, and the potential of nano-inclusions and quantum dots in improving TE efficiency. The review emphasizes the importance of nanoengineering in achieving high-performance TE materials and outlines future research directions, including the development of new materials and the optimization of existing ones for practical applications. The review concludes that further research is needed to improve the efficiency and scalability of TE materials for widespread use in energy conversion and refrigeration technologies.This review summarizes recent advances in the development of high-performance thermoelectric (TE) materials with a high dimensionless figure of merit (ZT). Thermoelectric materials convert thermal energy directly into electrical energy and are used for power generation and refrigeration. Over the past decade, significant progress has been made in improving the ZT of TE materials through nanostructuring, which allows for better control of thermoelectric parameters such as electrical conductivity, Seebeck coefficient, and thermal conductivity. Nanostructures enable the decoupling of thermal and electrical transport by introducing new scattering mechanisms, leading to enhanced TE performance. The review discusses various high-ZT materials, including Bi–Te alloys, skutterudite compounds, Ag–Pb–Sb–Te quaternary systems, half-Heusler compounds, and high-ZT oxides. Strategies for improving TE performance include reducing lattice thermal conductivity through nanostructural design, optimizing the power factor, and enhancing the Seebeck coefficient. The review also highlights the importance of nanostructuring in achieving high ZT values and discusses future directions for improving TE materials. Key findings include the use of nanostructures to reduce thermal conductivity, the role of grain boundaries and interfaces in enhancing TE performance, and the potential of nano-inclusions and quantum dots in improving TE efficiency. The review emphasizes the importance of nanoengineering in achieving high-performance TE materials and outlines future research directions, including the development of new materials and the optimization of existing ones for practical applications. The review concludes that further research is needed to improve the efficiency and scalability of TE materials for widespread use in energy conversion and refrigeration technologies.