The field emission properties (FE) of a heteroarchitecture comprised of gadolinium hexaboride nanoparticles uniformly decorated over Cu₂O nanoneedles (GdB₆/Cu₂O) have been investigated at the base pressure of ~1×10⁻⁸mbar. Under the optimized pulsed laser deposition (PLD), a well-adhered coating of GdB₆ nanoparticles on chemically synthesized cuprous oxide (Cu₂O) nanoneedles has been obtained. A plausible growth mechanism of the hierarchical assembly of GdB₆ nanoparticles on the Cu₂O nanoneedles is explained on the basis of structural analysis carried out using SEM and TEM. A low turn-on field of ~2.3 Vμm⁻¹(to draw an emission current density ~1μAcm⁻²) is observed along with stable emission current at the preset value of ~2μA over 4 h. The enhanced emission behaviour of the GdB₆/Cu₂O heteroarchitecture, in contrast to the pristine Cu₂O nanoneedles, is attributed to its high aspect ratio and low work function. The observed FE results demonstrate GdB₆/Cu₂O heteroarchitecture as a potential candidate for application in various vacuum nano/microelectronic devices.