Scintillators and photodetectors are fundamental tools used in luminescence spectroscopy and microscopy for detecting and measuring ionizing radiation and optical signals. The scintillators convert the high-energy radiation into visible or near-visible light, and detectors measure the visible or near-visible light by converting it into an electrical signal. Hence, a scintillator combined with an appropriate detector is required to detect high-energy radiations such as X-rays or gamma rays, while only a photodetector is required to detect visible or near-visible light. The understanding and application of these components have revolutionized several fields, such as medical imaging, nuclear physics, environmental monitoring, and particle physics. This chapter offers an in-depth analysis of the principles of scintillation, various types of scintillators, advancements in scintillator technology, the mechanisms of photodetection, various types of photodetectors, and current scientific and technological demands.