Thin films of antimony-doped tin oxide (ATO) have been prepared by the sol-gel dip-coating (SGDC) process, using tin(II) chloride dehydrate (SnCl2, 2H2O) and antimony (III) chloride (SbCl3) as host and dopant precursors respectively. The effect of antimony doping on the structural, thermal, electrical and optical properties of the samples were investigated. The structure of the (ATO) powders was analysed by X-ray diffraction (XRD) and the microstructure of the thin films by scanning electron microscopy (SEM). It was clear from these investigations that its structure is tetragonal rutile type and that an increase in Sb-doping decreases the crystallite size of the (ATO) particles. Thermal analysis by differential scanning calorimetry (DSC) showed that the crystallization temperature is about 370 °C whatever the Sb-doping amount. The lowest resistivity (2.6 × 10−3 ${\rm \Omega}$ cm) was obtained for the 5% Sb-doped film and the value of the band gap (3.69 eV) for the undoped film, increases slightly with Sb-doping increasing for the doped films.