Reflector antennas have been still one of the best solutions to requirements for cost effective, high gain, high performance antenna systems and therefore have been used in various areas of electrical engineering, ranging from telecommunications and radars to deep‐space exploration and radio astronomy. Consequently, the majority of radar, ground station and spacecraft high gain antennas are reflector antennas. Different types are used such as plane, corner, singly and doubly curved, and single and multiple reflectors. That depend on applications, frequencies, polarizations, resulting radiation patterns, etc. Basic theoretical principles, analytical methods, numerical simulations, experimental results and various practical issues, which can facilitate the design of reflector antennas, are described. The more general design uses geometrical and physical optics. The generalized diffraction synthesis technique can be utilized to produce various radiation patterns such as pencil‐beams and contoured beams, and to enhance the radiation characteristics of an existing canonical or distorted system. The reliability and accuracy of analytical/numerical techniques have allowed employment of commercial or customized computer programs in the performance evaluation and design of reflector antennas considering various parameters such as sidelobe levels at far‐angular regions and cross‐polarization control.