Highly oxygenated compounds in bio-oil produce negative properties that have hampered fuel development. Copyrolysis with plastics has increased hydrogen content in past research. Py-GC/MS analyses for two wood types (pine and oak) and three plastic types (polystyrene, polypropylene and high density polyethylene) established temperature, heating rate and residence time to produce a typical bio-oil. Analysis of various plastics to wood ratios by Py-GC/MS showed that a 50:50 wt/wt ratio produced the highest level of low molecular weight compounds best for fuel viscosity. Copyrolysis was performed on a laboratory-scale reactor at these temperature and wood-to-plastic ratios. Copyrolysis lowered bio-oil oxygen content and increased carbon content. Lower water content, acid value and viscosity also resulted, improving bio-oil suitability for fuels. Cross reactions between wood and plastics formed no new chemical species during copyrolysis. These results indicate that copyrolysis of waste plastics with woody biomass has potential for improving bio-oil properties for fuels production.