The most detailed measurements of the energy gap in Al by the tunneling technique have been made using Al–Al2O3-Pb junctions. Determination of the energy gaps from the I–V curves of these junctions is more precise than previous results using Al–Al2O3–Al tunnel junctions. The chief difficulty with the Al–Al2O3–Al junctions has been the lack of definition in the I–V curves, especially near Tc. Al–Al2O3–Al junctions, in which the energy-gap voltages can be read from the I-V curve with very little ambiguity up to T/Tc ≈ 0.99, are reported here. For the majority of the junctions studied, the temperature dependence of the normalized gap Δ(t)/Δ(0) shows very little scatter (T = 0.34 °K to T = Tc) and agrees closely with the BCS theory. However, a consistent small deviation is observed, with the measured gap values being slightly higher than the BCS prediction. The mean value of 2Δ(0)/kBTc obtained from 21 different junctions is 3.53 with an r.m.s. deviation of ± 0.02.