Electronic conductivity of Langmuir−Blodgett monolayers of phenylethylthiolate-protected gold nanoparticles was examined in vacuo at different temperatures. It was found that the ensemble conductance exhibited a volcano-shaped dependence on the interparticle separation, which was ascribed to the mediation of interparticle charge transfer by the π−π stacking of the phenyl moieties from neighboring particles. Additionally, the ensemble conductance was found to increase with increasing particle core size, most probably due to enhanced interparticle electronic (dipolar) interactions. Temperature dependence of the conductivity profiles suggested a thermal activation mechanism for the interparticle charge transfer driven by electron hopping. Thermally induced core motion was suspected to account for the different degree of temperature dependence of the ensemble conductivity with particle core size. Such ligand-mediated charge transfer may be exploited for sensing and device applications.