The purpose of this work is to design and manufacture low cost, efficient terahertz (THz) diffraction gratings using a 3D printing technique. We performed theoretical modeling and numerical simulations to determine the components’ optimal parameters; then, we proceeded to 3D printing and final production of the desired component. Experimental characterization has shown that the components that we manufactured offer very satisfactory performances despite their insignificant cost, which is promising for providing THz components with a very high quality/price ratio.