In this work, a peridynamics-based representative volume element approach is implemented to estimate the effective tensile modulus of nanomodified epoxy resins. The results obtained through this homogenization procedure are then used as input for the analysis of nanocomposite fracture toughness, which is carried out by exploiting a classical continuum mechanics-peridynamics coupling strategy. In the coupled model, the small-scale heterogeneity of the crack tip region is preserved by implementing the recently proposed intermediately-homogenized peridynamic model. Comparison to experimental data confirms the capability of the peridynamics-based approaches to properly model the effective tensile modulus and fracture toughness of polymer-based nanocomposites. •Nanocomposite effective tensile modulus is derived through a PD-based RVE homogenization.•RVE homogenization results are used as input for the fracture toughness analysis.•Effect of nanomodification on the fracture toughness is studied through a FEM-PD coupling strategy.•PD-based approaches operate at different length scales.•Numerical results are calibrated by performing tensile tests and mode I fracture tests.