1H NMR spectra of epoxy-fused cyclopentane derivatives have been computationally investigated with density functional calculations in order to unravel the shielding effect of the epoxy ring on the 1H NMR chemical shifts of N-substituted epoxy-fused cyclopentane-3, 5-diol derivatives. Both 1H NMR chemical shifts and spin–spin coupling constants have been calculated with the WP04/cc-pVTZ level of theory in solution. The WP04/cc-pVTZ// B3LYP/6-31+G(d) methodology has been found to reproduce the best experimental results on epoxy-fused cyclopentane derivatives. This study is expected to lead experimentalists in their endeavour to characterize epoxy-fused cyclic systems with ease.