Abstract In the last two decades of the new millennium, many innovative processes have been invented to fabricate metallic microparts and structures. In this article, we focus entirely on micro Additive Manufacturing (µAM), or more often called micro 3D printing process. We intend to provide the most comprehensive classification of µAM to date, and our insights to the future trend in this area. Example of their applications, available metals and alloys, geometry constraints, processing speed and feature resolution are summarized here. This forms a concise guide to the µAM process selection, should certain part or structure be required at microscale.