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 e€ect of processing variables on void content measured from the microstructure and laminate mechanical properties. Time at pressure had the greatest e€ect on strength and moduli.