Abstarct: In this thesis, the structural and optical properties of CuInS2 thin films prepared using spray pyrolysis method on glass substrates have been investigated. Then, the effects of different growth parameters such as spray nazzel to the substrate distance (35, 40 and 45 cm), substrate temperature (300, 350, 400 and 450 °C), annealing temperate and deposition rate (3, 5 and 10 ml / min) on their structural and optical properties were studied. Structural properties of the samples were studied by a Field Emission Scanning Electron Microscope (FESEM) and a X-ray diffractometer (XRD). To study the optical propery of the samples, a (UV-Vis) spectrophotometer was used to measure the transmittance spectra. The XRD spectra recorded for the samples confirmed the formation of the tetragonal structure of CuInS2 with preferential (112). The result obtained from XRD data confirmed that increasing the subatrate annealing temperature causes the samples become amorphous. The recorded FESEM images from the surface of the samples showed that annealing causes increase in the grain size. It has also been observed that by increasing the diposition rate, the crystallite size sligthy decreases and the band gap increses. The study of the effect of the spray nazzel to the substrate distance showed that this parameter has a significant effect on the structural and optical properties of the samples. As the distance increases, the direct band gap of the samples increases by 0.38 eV. Also the result showed that the optical absorption for all samples are around 104 cm-1 which indicats the CuInS2 thin films are good for solar cell application.