Thin film microfluidics are developed for a wide range of applications, including the synthesis of various types of nanocarbon material, involving both ‘top down’ and ‘bottom up’ continuous flow processing. This type of processing addresses scalability at the inception of the science, and is applicable not just to the synthesis of nanocarbon, but also composites or hybrid material where one or more components is nanocarbon. This review introduces the different types of thin film microfluidics where the liquid is subjected to shear stress (mechanical energy), and then provides a comprehensive treatise of controlling the fabrication of nanocarbon. The shear stress offers scope for controlling the shape, morphology and size of carbon nanomaterial, with the prospect of high green chemistry metrics of the processing. The use of thin film microfluidics has potential where conventional batch processing is limited in terms of practical convenience, and indeed where some novel forms of carbon and composites thereof are not accessible using traditional approaches.