3D printing is an innovative and sustainable technology that employs robots to construct concrete structures in layers, enabling the creation of complex designs that traditional methods struggle to achieve. This technology has the potential to reduce labor costs and construction times, minimize waste, and improve sustainability. The performance of the resulting 3D-printed structure is primarily influenced by the properties of the developed mixtures and the specific printing parameters used. Therefore, this paper primarily provides fundamental information on the behavior of different supplementary cementitious materials when used in 3D-printed cementitious composites. Moreover, the key rheological parameters such as flowability, buildability, extrudability, pumpability, and open time have been discussed. Finally, the paper addresses current challenges and offers recommendations for future research to promote the widespread adoption of 3D printing technology in the construction industry.