Abstract Terahertz (THz) science is widely recognized as the new frontier of applied electromagnetics, bridging the gap between microwave- and photonics-based applications. THz radiation, spanning frequencies over three orders of magnitude, namely from 0.1 THz to 10 THz, combines the advantages of a submillimetric wavelength with a centimeter scale penetration depth while featuring a non-ionizing character. This unique combination cannot be found elsewhere in the frequency spectrum, yet it exactly matches the demand of imaging applications in diverse fields such as material characterization, quality control, authentication, and cultural heritage. In this topical review, we specifically address the progress that THz imaging techniques based on time-domain spectroscopy (TDS) have made in the last three decades in the abovementioned contexts. Emphasis is given in their application to ( i ) the analysis of emerging materials (two-dimensional materials, phase-change materials, etc), ( i i ) industrial applications with high social impact (e.g. food safety, anticounterfeiting, etc), ( i i i ) cultural heritage studies (e.g. image reconstruction, conservation studies, etc). With a careful selection of works in the field, this topical review offers a bird’s eye view on the state of the art of THz-TDS in diverse application-oriented contexts, while addressing the reader towards the most promising research axes in the field of THz science.