Sensors are integral to modern society, evolving from basic mechanical devices to cutting-edge nanotechnology-based systems. Recent years have seen rapid advancements, such as microelectromechanical systems (MEMS), internet of things (IoT)-enabled, and artificial intelligence (AI)-integrated sensors, impacting applications across homes, healthcare, industry, and the environment. Among emerging smart materials, perovskites (ABX3-structured compounds) stand out due to their tunable electronic, dielectric, and piezoelectric properties, making them highly attractive for next-generation sensor devices. Notably, lead-based perovskites exhibit excellent performance but present toxicity and stability challenges, leading to increased research into lead-free alternatives like BaTiO3, SrTiO3, and KNN. While these lead-free materials show promise for safer, high-performance sensors in photodetection, gas sensing, and environmental monitoring, limitations such as lower efficiency and moisture instability must be addressed. This chapter highlights the significance, prospects, and challenges of perovskite materials in smart sensors, as well as efforts toward eco-friendly and scalable solutions.