Terahertz (THz) radiation describes electromagnetic (EM) radiation with a frequency of between 0.1-10 THz. There has been widespread interest in THz imaging which has been demonstrated in numerous applications from medical to non-destructive evaluation (NDE) due to the unique properties of radiation at these wavelengths. Current THz imaging systems suffer many drawbacks including the requirement of expensive components, slow imaging frame-rates and poor resolution. In this thesis, a digital THz holography system is demonstrated which could offer a high-performance and potentially low-cost alternative. The design and implementation of the first full video-rate (50 Hz) THz digital holography system is presented in this thesis. The system operates with coherent radiation of 2.52 THz (118.8 µm) and features low-cost optical components. The system's ability for imaging concealed objects is shown which suggests potential as a NDE tool. The potential to be used as a 3D depth imaging tool is also shown. The publication relating to this work along with the movies and data-set can be found from the following reference along with in the thesis data-set: M. Humphreys, J. Grant, I. Escorcia-Carranza, C. Accarino, M. Kenney, Y. Shah, K. Rew, and D. Cumming, "Video-rate terahertz digital holographic imaging system," Opt. Express 26, 25805-25813 (2018).