Adaptive optics are used to improve image quality of optical systems by sensing and correcting dynamic wavefront disturbance in real time. The same methods also serve to improve beam quality for optical systems that transmit light through turbulent media like the Earth’s atmosphere. This course covers the basic principles of adaptive optics with emphasis on large ground-based telescopes. We explore the effect of dynamic aberration, the key components of an adaptive optics system with examples of each, system integration and control strategies, and performance predictions and limitations. The course is illustrated throughout with examples from fielded systems spanning astronomy, laser communications, ophthalmology and other applications. We touch on advanced concepts including laser guide stars, multiconjugate and tomographic imaging systems, as well as numerical methods for image restoration that complement adaptive optics.