Spectra of GeS have been obtained in a chemiluminescent flame produced by the reaction Ge + OCS → GeS + CO. Neither of the known band systems, D1Π- X1Σ + and E1Σ +- X1Σ +, was observed, but two new band systems in the regions 350-400 and 420-650 nm were obtained. By comparison with similar systems in isovalent molecules, these were assigned as b3Π 1- X1Σ + and a3Σ +- X1Σ +, respectively. Vibrational assignments were made with the help of the germanium isotope effect and vibrational constants were obtained for the states involved. Approximate Morse potential Franck-Condon factors were computed and were shown to fit the general trend of the intensity distribution for both systems. Addition of active nitrogen to the flame was shown to increase the intensity of the b- X system by an order of magnitude while hardly affecting the a- X system. Constants (in cm -1) obtained for the two new states are: a3Σ +: Te = 21986.3 ± 2.3, ωe = 388.9 ± 1.0, ωexe = 1.35 ± 0.11; b3Π 1: Te = 27192.0 ± 1.8, ωe = 435.4 ± 1.1, ωexe = 1.68 ± 0.20.