New glass-forming systems based on sulfides are reported as infrared-transmitting materials used for fabrication of optics. The systems consist of Ga2S3, Sb2S3, and a third component, CsCl or SnS. They do not contain Ge, As, and Se, which are conventionally used elements for chalcogenide glasses. The transmission range in the infrared region almost covers the atmospheric windows. Furthermore, the glasses with appropriate compositions are stable against the crystallization and should be suitable for mold shaping.