Efficient electron transport layers (ETLs) play a pivotal role in the performance of solar cells. In recent years, Indium sulfide (In₂S₃) has been studied as a promising ETL in CuInGaS(e)₂, Cu₂ZnSnS(e)₄, and perovskite solar cells. Despite several studies on spray-deposited In₂S₃, there is no complete experimental investigation on In₂S₃ thin films. The effect of the molar ratio of S/In and the type of indium precursor on the structural, morphological, optical, and electrical properties of sprayed-In₂S₃ layers has been studied. Films were characterized using x-ray diffraction, scanning electron microscopy (SEM), optical transmission (UV-Vis), Mott–Schottky analysis, four-point probe, and cyclic voltammetry measurements. The crystallinity and morphological characteristics are strongly influenced by the type of indium salt, where indium acetate precursor results in a highly porous film compared with nitrate and chloride precursors. The chloride precursor demonstrates better crystallinity and considerably lower sheet resistance. All films are n-type with a carrier concentration in the range of ∼2  ×  10¹⁷ to ∼2  ×  10¹⁸  cm^−  3, with an indirect bandgap of 2.0 eV.