In this chapter, the background knowledge on ionizing radiation is classified based on the nature of the photons and particles, and recent advances in the emerging field of metal-halide perovskite (MHP)-based radiation detection are presented. The chapter introduces the underlying principles of ionized particle and high-energy radiation detection and emphasizes the critical performance metrics. Then, the appropriate fundamental characteristics and advantages of MHPs for radiation detection are discussed in detail. After that, recent accomplishments in detecting α-, β-, γ-, and X-rays using halide perovskites are summarized. The chapter’s last part focuses on current challenges and future perspectives.