The electronic states of a range of Fe‐Si alloys were investigated by x‐ray and ultraviolet photoelectron spectroscopy. Previous work has shown that in Fe‐Si alloys, the 6.5‐wt % Si‐Fe alloy has the optimum soft magnetic properties because of its zero magnetostriction. The binding energy (BE) of the Fe 2p, Fe 3s, Fe 3p, and Si 2plevels and the Fe 3dvalence‐band structures of Fe‐Si alloys were measured over the range from 0 to 7 wt % Si. The BE of the Fe 3sand Fe 3plevels and the Fe 3dvalence band of Fe‐Si alloys showed small shifts of the peaks toward higher BEs than pure Fe. These peak shifts are related to the change in density of Fe 3dstates with the addition of Si: the decrease in the density of states near the Fermi energy, the decrease in the energy difference between the majority and minority spin bands, and the increase in the number of electrons with minority spin. The results of the photoelectron spectroscopic analyses agree with the observed decrease in saturation magnetization from 2.15 T for pure Fe to 1.80 T for 6.5‐wt % Si‐Fe.