Mid-infrared laser polarization spectroscopy (IRPS) is a powerful diagnostic technique suitable for the quantitative measurement of species concentration and temperature. IRPS is well suited to reactive multiphase flows and is not affected by the presence of particles and other nanostructures. It has the potential to detect species that have no accessible single-photon electronic transition in the UV/Visible range. In this review, an overview of the various contributions that have been devoted to the development and application of IRPS are summarized and discussed. The basic theoretical framework is presented and the nature of the IRPS experiments is described. Then, several types of IRPS applications are reviewed, including the measurement of the concentration of minor species and the temperature, the study of molecular dynamics and collision energy transfer, and the feasibility of 2D imaging with high spatial resolution. Finally, future prospects, required improvements, and potential application fields of IRPS are provided.