Binder jetting, also known as 3D printing, is an additive manufacturing (AM) technology utilizing a liquid-based binding agent to selectively join the material in a powder bed. It is capable of manufacturing complex-shaped parts with a variety of materials. This paper provides an overview of binder jetting of metals with a discussion about the knowledge gaps and research opportunities. The review deals with two parameter categories in terms of the material and process and their impacts. The achieved density, dimensional accuracy, and mechanical strength are summarized and analyzed. Further in-depth consideration of densification is discussed corresponding to various attributes of the packing, printing, and sintering behaviors. Though binder jetting has attracted increasing attention in the past several years, this fabrication process is not well studied. The understanding of powder spreading process and binder-powder interaction is crucial to the development of binder jetting but insufficient. In addition, the lack of investigation on the mechanical behavior of binder jetting metal part restricts the actualization of its wide-range applications.