The A1II–X1Σ+ transition of the SiH+ molecule has been observed in the emission spectrum of a hollow-cathode discharge through helium containing a trace of silane. The analysis of five bands yields the molecular constants Bc″ = 7.6603 cm−1, ΔG″(1/2) = 2088.69 cm−1, Bc′ = 4.9125 cm−1, ΔG′(1/2) = 390.17 cm−1, and v(0–0) = 25 025.20 cm−1. Because of the shallowness of the upper-state potential curve, a good estimate of the dissociation limit is obtained: D00(SiH+) = 3.20 ± 0.08 eV. This dissociation limit leads to an ionization potential of 8.01 ± 0.08 eV of SiH. The SiH+ molecule is tentatively identified in the solar spectrum and the possibility of detecting interstellar SiH+ is briefly discussed.