3D printed concrete (3DPC) technology is relatively new, and it still has many challenges to overcome if it is going to replace, at least in part, conventional concrete construction. One of the difficulties is the lack of proper reinforcement for printing building scale structures. Different ideas proposed to reinforce 3D printed concrete can be categorized based on the material (e.g., steel, thermoplastic, FRP, and other materials) or stage to place reinforcement (pre-installed, in-process, and post-installed reinforcement). However, limited available test data and even fewer examples of the use of the proposed reinforcement concepts in actual construction have retarded the development of this advanced technology. Before developing some novel concepts, looking back to review what has been achieved in this regard is a necessary step to move forward. This section will discuss the recent attempts to reinforce 3D printed concrete based on different stages to place the reinforcement.