Well characterised dough moulding compound (DMC) and woven glass fibre-reinforced phenolic (GWP) recyclate fillers have been investigated as reinforcements for polypropylene. Consideration is given to the use of treatment systems to enhance fibre-matrix interfacial bonding and mechanical properties. Using a combination of grafted polymer and coupling agent, significant increases in recyclate/polypropylene composite properties are possible, the levels obtained critically depending on glass fibre content. The role of the recyclate particles in initiating failure is discussed, as is the influence of compounding route on recyclate integrity and molecular mass changes to the host polymer matrix.