In this study, we evaluated the use of bio-oil and biochar on epoxy resin. Bio-oil and biochar were obtained from the pyrolysis of wheat straw and hazelnut hull biomass. A range of bio-oil and biochar proportions on the epoxy resin properties and the effect of their substitution were investigated. TGA curves showed improved thermal stability for degradation temperature at the 5% (T5%), 10% (T10%), and 50% (T50%) weight losses on bioepoxy blends with the incorporation of bio-oil and biochar with respect to neat resin. However, decreases in the maximum mass loss rate temperature (T_max) and the onset of thermal degradation (T_onset) were obtained. Raman characterization showed that the degree of reticulation with the addition of bio-oil and biochar does not significantly affect chemical curing. The mechanical properties were improved when bio-oil and biochar were incorporated into the epoxy resin. All bio-based epoxy blends showed a large increase in Young’s modulus and tensile strength with respect to neat resin. Young’s modulus was approximately 1955.90 to 3982.05 MPa, and the tensile strength was between 8.73 and 13.58 MPa for bio-based blends of wheat straw. Instead, in bio-based blends of hazelnut hulls, Young´s modulus was 3060.02 to 3957.84 MPa, and tensile strength was 4.11 to 18.11 Mpa.