Advanced military and microwave systems are demanding increased integration, reliability, radiation hardness, compact size, and lower cost when produced in large volume, whereas the microwave commercial market, including wireless communications, mandates low‐cost circuits. Monolithic microwave integrated circuit (MMIC) technology provides an economically viable approach to meeting these needs. This article deals with MMIC fabrication, substrates, matching networks, active devices, and monolithic design of microwave components and circuits, including device modeling and EM simulations. Typical monolithic microwave circuits and their performance, and MMIC packaging are also discussed.