Processing of glass-mat thermoplastics (GMTs) by hot-Pow compression moulding represents a complex physical process with non-isothermal and non-Newtonian conditions. To increase the understanding of process and property interactions, a series of statistically designed experiments have been conducted on Pat plaques. Processing variables were ranked in order of importance for increased laminate properties. Processing models were generated using regression techniques describing the eect of processing variables on void content measured from the microstructure and laminate mechanical properties. Time at pressure had the greatest eect on strength and moduli.