Superconducting tunneling junctions have been prepared on Nb, Nb3Ge, V3Si, ErRh4B4, and Au base electrodes with either Pb or In counterelectrodes using a barrier of oxidized Er or Lu. Nb/RE/oxide/Pb Josephson junctions with very low leakage have been studied in detail. The ease of fabrication and the stability of the junctions under thermal cycling suggest that they may have technological significance.