In this paper, we reviewed some of the microelectromechanical system (MEMS) research efforts for high frequency applications. The efforts can generally be divided into two areas: planar reconfigurable transceivers and phased arrays using MEMS devices. For the planar transceivers, the interest is in demonstration of RF MEMS devices with a focus on integration issues including architectures and fabrication. Our goal is to establish building blocks for compact, smart transceivers that have beam forming and tuning functionality. For phased-array applications, system architectures were demonstrated for quasi-optical systems and phased arrays. The purpose is to demonstrate beam forming and steering functionality using MEMS devices instead of expensive phase shifters.