This paper lays out the main procedures for performing morphological characterisations of Long Glass Fibre (LGF) composites with particular reference to the sheet extrusion and thermoforming processes as they may be configured for production. The techniques used, including optical microscopy, scanning electron microscopy and image analysis, are described both with regard to their laboratory application to these materials and to their potential for monitoring the performance of the industrial manufacturing process. Results obtained from the different techniques at the three various stages of the manufacturing route are presented and discussed in terms of the structure property relationships obtained and the reinforcing fibre mat system typical of these types of material.