3D printing is disrupting the design and manufacture of electronic products. 3D printing electronics offers great potential to build complex object with multiple functionalities. Particularly, it has shown the unique ability to make embedded electronics, 3D structural electronics, conformal electronics, stretchable electronics, etc. 3D printing electronics has been considered as the next frontier in additive manufacturing and printed electronics. Over the past five years, a large number of studies and efforts regarding 3D printing electronics have been carried out by both academia and industries. In this paper, a comprehensive review of recent advances and significant achievements in 3D printing electronics is provided. Furthermore, the prospects, challenges and trends of 3D printing electronics are discussed. Finally, some promising solutions for producing electronics with 3D printing are presented.