Structural, morphological, optical and electrical characteristics of zinc sulfide (ZnS) and boron doped zinc sulfide (ZnS:B) films deposited on glass substrates by ultrasonic spray pyrolysis (USP) method and heated up to 350±5 °C were studied. B doping at various concentrations did not change the crystal structure of the ZnS film and it also did not cause any significant change in the size of crystallites. Maximum transmittance values of the B doped ZnS films increased parallel to doping rate. Transmittance edges showed shifting towards smaller wavelengths due to the effect of B doping. B doping increased optical band gap values. Scanning electron microscopy (SEM) images of the film surfaces showed that B doping did not cause any significant change in grain sizes of the films. Presence of all expected elements in the films including Zn, S and B was confirmed through Energy Dispersive Spectrometry (EDS) analysis. Significant peaks of foreign phases on the film surfaces were observed through Fourier Transform Infrared (FT-IR) spectroscopy. The electrical resistivity values of the films were calculated by means of current-voltage characteristics.