The ZnS nanoparticles doped with Mn and Nd were synthesized by applying a wet chemical precipitation method using (NH4)2S as the sulfur source. The co-doped ZnS nanopowders with pure sphalerite phase were confirmed by X-ray diffraction (XRD). The influences of co-doped Mn and Nd on the ZnS crystallites, band-gap, and luminescence characteristics have been investigated. Ultraviolet–visible (UV–Vis) spectroscopy revealed the band gap enhancement of the co-doped ZnS. The photoluminescence in both visible and near infrared (NIR) regions, induced by incorporation of Mn2+ and Nd3+ into ZnS host, indicated that the co-doped ZnS nanocrystals can serve as a promising candidate for innovative photoluminescent materials.