There is an increasing demand of renewable energy resources due to various factors that affect our environment significantly. Thermoelectric energy can be one such potential resource for us to circumvent the need of energy demand and to improve our lifestyles while preserving the environment. Perovskites materials are interesting in sense to show good thermoelectric performance. Most of the lead-based perovskites are the key elements to show reasonable thermoelectric performance. But due to their toxic nature and less reliability, researchers are now tending to look for lead-free materials. Lead free perovskites such as CsSnI3, double perovskite (e.g. A2GeSnF6, Cs2MGaBr6 etc.), anti-perovskite (e.g. X3BN) and its nanostructures are showing interest due to its potential application for thermoelectric materials [1–4]. The observed zT parameters for such perovskites are found to be in the range of 0.8–1.0 and some lead-free perovskites found to shows zT > 1 [1, 2]. The key point in having large zT, i.e., high conversion efficiency of waste heat into electrical energy is the basic requirement of the thermoelectric material. The high conversion efficiency of thermoelectric materials depends on several factors such as Seebeck coefficient, electrical conductivity and thermal conductivity etc. In this chapter, we will discuss in details about the different aspects, advancement, its basics and the future scope of lead-free perovskites materials for its potential applications in thermoelectric.