Three dimensional (3D) printing technologies, known as the additive manufacturing, have been attracting extensive interests in various fields, including the academic world, industries and even daily life. It has special capabilities that can be used for increasing shape or structure complexity and fabrication efficiency, while reducing the waste materials, capital cost and design cycle for manufacturing. Among these, fabrication of functional components or devices for microelectronic systems with 3D printing technologies is still an emerging field. Recently, a series of 3D printed functional components and devices for electronics have been reported, especially with the widely used direct ink writing 3D printing. This paper will focus on materials and practical applications of 3D printing for electronic units and systems, including microelectrodes, supercapacitances, electronic circuits, batteries and so on. The implementation of 3D printing for electronics with advanced materials will have great advantage in terms of performance, microstructures, product flexibility and tailored shape along with low cost, less waste and high efficiency.