Light-emitting diodes have emerged as versatile and affordable excitation sources for photoacoustic imaging, offering a safe, compact, and energy-efficient alternative to conventional pulsed lasers. Continuous improvements in semiconductor efficiency, thermal management, and pulse-driving electronics have increased optical fluence and stability, making LED-based photoacoustic imaging suitable for real-time imaging at clinically relevant depths. This chapter reviews the underlying physical principles of LED operation, historical milestones in LED-based photoacoustic imaging development, and system architectures that integrate LED illumination with ultrasound detection. Representative preclinical and clinical studies are highlighted to illustrate diagnostic capabilities in vascular, rheumatologic, and perfusion imaging. The chapter also examines emerging benchmarking methodologies, standardization efforts, and translation pathways that will guide future clinical validation of LED-based systems. Finally, we discuss current limitations, ongoing engineering innovations, and future directions that position LED-based technology as a practical and scalable pathway toward accessible and translational photoacoustic imaging.