Continuous advancement in terahertz technologies have drawn interest in manufacturing and rapid prototyping of optical components suitable for the terahertz spectral range. One of the approaches of realizing such optical components is additive manufacturing, which has been studied in recent years for fabricating terahertz optical elements including lenses, filters, and waveguides. Stereolithography, with its superior resolution compared to other prevalent additive manufacturing techniques, could be an efficient way of fabricating terahertz elements with sub-wavelength scale architectures. However stereolithographically fabricated terahertz optical elements or metamaterials have not been studied extensively. In fact there is lack of information on the terahertz optical properties of materials available for stereolithography, which impedes first-principle calculations and further development of terahertz structures using stereolithography. In this thesis, we sought to fill this knowledge gap by determining the terahertz optical properties of materials commonly available for stereolithography. Utilizing the determined material properties, terahertz optical elements and metamaterials have been designed and experimentally realized. One-dimensional terahertz photonic crystals and defect modes within such crystals have been demonstrated for the first time through a single-step stereolithography from a single dielectric material. Mechanical tunability of the photonic bandgap and defect modes of the one-dimensional photonic crystals was realized experimentally. In addition, stereolithographically fabricated anisotropic metamaterial composed of slanted columnar structures have been explored for the first time. This metamaterial design was successfully demonstrated as a single layer, as well as constituent layers of one-dimensional photonic crystal structures. Fabrication of terahertz optics with desired curvature have also been investigated using two different approaches. Off-axis parabolic reflectors have been demonstrated first by metalizing stereolithographically fabricated polymer base, then by employing one-dimensional photonic crystal structure into design. In conclusion, stereolithography has been introduced as a new paradigm for fabrication of custom terahertz elements and novel metamaterials with tailored optical properties.