This work presents an overview of terahertz (THz) spectroscopy with a focus on its implementation within microfluidic platforms. Such platforms are of great interest because they can enable label-free and reagent-free sensing. However, they must be implemented with thought towards the incorporated materials and structures as they can greatly impact the bandwidth, frequency resolution, signal-to-noise ratio, and dynamic range of the measurements. This review explores such relationships with insight given on the design and material considerations for the effective integration of THz spectroscopy in microfluidic platforms. The review also describes recent work on the application of THz spectroscopy to biomaterial analyses on increasing scales, targeting DNA, proteins, cells, and tissues.