Fast pyrolysis bio-oil was employed as a source of phenolic compounds in the production of a bio-based polymeric network. The bio-oil was reacted with epichlorohydrin in alkaline medium using benzyltriethylammonium chloride as a phase transfer catalyst. The amount of free phenolic hydroxyl groups before and after modification was quantified through P-31-NMR spectroscopy; and the epoxy content of the bio-oil upon the chemical functionalization was measured by means of a titration using HBr in acetic acid solution. Grafting of epoxy functions onto the monomer`s structure was studied by FTIR. Likewise, -resorcylic acid was also modified with reactive epoxy moieties, and used as low molecular weight comonomer. The epoxidized derivatives of the bio-oil were cured in epoxy polymers with 4-dimethylaminopyridine. Thermo-mechanical characterization showed that the obtained materials behave as thermoset amorphous polymers, exhibiting modulus values ranging from approximately 1.5-3.4 GPa at room temperature and glass transition temperatures above 100 degrees C. POLYM. ENG. SCI., 58:1296-1307, 2018. (c) 2017 Society of Plastics Engineers