This chapter gives an overview of recent developments in three main classes of intermetallic thermoelectric materials, namely the half-Heuslers, skutterudites and Zintl-type materials. The first two groups have been heavily investigated and are leading contenders for application in thermoelectric waste heat recovery owing to their good power factors, with peak values of 5–6 mW m⁻¹ K⁻² and figures of merit reaching ZT ≈ 1.5. Zintl phases cover a wide range of structure types, and in particular antimonide compositions can support excellent thermoelectric performance. Key examples include n-type Mg₃Sb₂, which rivals Bi₂Te₃-based alloys for near room temperature operation, and p-type Yb₁₄MnSb₁₁, which is an outstanding thermoelectric at very high temperatures. The emphasis throughout this chapter is on the relationships between composition, structure, processing and thermoelectric properties.