We apply the recently developed plasmon hybridization method to a solid nanosphere interacting with a metallic surface. We show that the plasmon energies of the nanoparticle exhibit strong shifts with nanoparticle−surface separation. Depending on the energy of the surface plasmon, nanoparticle plasmons can either red shift or blue shift with decreasing nanoparticle−surface separation. The shifts can be explained as resulting from image-like interactions with the metal surface and, more importantly, through hybridization between the nanoparticle plasmons and the delocalized surface plasmons of the substrate.