The crystal structure of Tl2TeS3 (orthorhombic, Pnma, No. 62, Z = 4, Pearson code oP24, a = 815.5(2) pm, b = 1352.6(6) pm, c = 596.48(15) pm, 600 unique reflections with Io > 2σ(Io), R1 = 0.0541, wR2 = 0.0997, GOF = 0.891, T = 298(2) K) in a new structure type has been determined. It can be understood as a LaI2-like arrangement of thallium cations and thiotellurite anions TeS32-. With a direct band gap of 1.61 eV and an indirect band gap of 0.9 eV, Tl2TeS3 is a new material that might be useful for thermoelectrical applications. The materials band gap is significantly lower compared to similar alkali metal systems. In addition, other than alkali metal thiotellurites, Tl2TeS3 is not sensitive toward the atmosphere (especially moisture). A synthetic strategy for improved thermoelectrical materials in the future might be a further reduction of the band gap by introduction of transition metals in such Tl/Te/S systems. Furthermore, density functional studies indicate that effects leading to structural distortions due to the thallium 6s2 lone pair are less important in sulfur compounds than in the analogous oxygen compounds.