Microreactors have become an efficient tool for many enzymatic reactions because the laminar fluid flow within the microchannel enables precise process control, rapid mixing, and short residence time. This paper provides a systematic overview of the application of reaction kinetics and the mathematical modeling of enzymatic processes in microreactors. Rapid heat and mass transfer and a high surface-to-volume ratio are usually the reasons why reactions in microchannels proceed faster and with higher yields and productivity compared to conventional macroreactors. Since there are no radial diffusion limitations, microreactors are also an effective tool for determining the kinetic parameters of enzyme-catalyzed reactions. By eliminating the mass transfer effect on the reaction rate, the kinetics estimated in the microreactor are closer to the intrinsic kinetics of the reaction. In this review, the advantages and disadvantages of using microreactors are highlighted and the potential of their application is discussed. Advances in microreactors result in process intensification and more efficient biocatalytic processes in line with the advantages offered by the application of microreactors, such as (i) higher yields, (ii) a cleaner and improved product profile, (iii) scale-independent synthesis, (iv) increased safety, and (v) the constant quality of the output product through (vi) accelerated process development. Furthermore, microreactors are an excellent tool for kinetic studies under specified mass transfer conditions, enhancing the capabilities of other methods.