Gas-phase ThS has been produced via the reaction of laser ablated Th with H2S. Rotationally resolved electronic spectra were recorded by laser-induced fluorescence (LIF) over the range 17500-24000 cm(-1) Resonance-enhanced multiphoton ionization was used in conjunction with a time-of-flight mass spectrometer to confirm the assignments of nine LIF bands to ThS. Using excitation of a ThS band centered at 22118 cm(-1), a dispersed fluorescence spectrum revealed a vibrational progression of the X-1 Sigma(+) ground electronic state and the term energies of two low-lying excited states ((3)Delta(1) and (3)Delta(2)). Two-color photoionization spectroscopy was used to study ThS+. An accurate ionization energy for ThS was obtained (54425(3) cm(-1)); ThS+ vibronic term energies up to v = 7 in the X-2 Sigma(+) ground state and v = 3 in the (2)Delta(3/2) first excited state were recorded. High-level electronic structure calculations, with inclusion of the spin orbit interactions yielded predictions that were in good agreement with the experimental data for ThS and ThS+. The spectroscopic properties of ThS/ThS+ are compared with those of the valence isoelectronic pairs ThO/ThO+, HfO/HfO+, and HfS/HfS+.