Thin films of antimony trisulphide (Sb$_{2}$S$_{3}$) were successfully grown on soda-lime glass substrates using the solution growth technique. The deposition time was varied between 1 h to 5 h and the other deposition variables were kept constant. The as-deposited layers were then subjected to post deposition heat treatments, with annealing temperatures in the range 100 °C to 300 °C. The effect of the post deposition annealing on the optical properties of the films were investigated. The optical characterisation was done using a UV spectrophotometer to investigate the absorbance, and transmittance versus wavelength measurements, to enable the determination of some important optical constants such as the optical absorption coefficient, energy bandgap, extinction coefficient, and the optical density. The value of the energy bandgap was 2.15 eV for the as-deposited layers, and decreased with annealing temperatures. The extinction coefficient was in the range 0.21 – 1.3, and the optical density was between 0.02 to 0.18.