This study aimed to determine the effect of Al-doping on the physical properties of ZnS thin films. The pulsed-laser deposition technique was used to prepare ZnS and Al-doped ZnS (AZS) thin films on soda-lime glass slides. The Al concentration of 0–6% was used. Further, XRD spectroscopy was employed to confirm the structures of the ZnS and AZS films, following which the values of parameters such as crystal plane spacing, crystallite grain size, microstrain, and dislocation density were calculated. Regarding ZnS, the result showed a broad pattern corresponding to the (111) plane of ZnS. There was a variation of 0.313–0.316 nm in the d-spacing, which decreased as the concentration of Al in the ZnS films increased. The crystallite size was found to be 0.80–671.24 nm. Notably, the crystallite size was affected by the Al concentration. The change in the a aluminum content from 0 to 8% make change in thee strain increase from 0.00046 to 0.0031. Also, as the Al-doping increased, the dislocation-density reduced from 1.54 to 0.00000221 mg.cm-3 . The values obtained in this work were consistent with published standards.