<p>In this work, transparent undoped and Al-doped TiO₂ thin films have been deposited on heated glass substrates through a spin coating sol-gel processing technique. Pristine TiO₂ and Al-doped TiO₂ thin films were synthesized with different Al doping ratio ranged from 0 to 6%. The influence of Al doping on the structural, morphological, optical, and electrical properties of TiO₂ thin films have been investigated. The synthesized samples were characterized via various techniques including X-ray diffraction (XRD), scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometry, photoluminescence (PL) spectroscopy and four-point probe measurements. The XRD analysis confirms the existence of the anatase TiO₂ phase with preferred orientation along the (101) direction. Furthermore, as the Al doping concentration increases, the crystallite size firstly decreased from 20 to 16 nm and then increased from 16 to 20 nm. The surface morphology analysis of the deposited Al:TiO₂ thin films reveals the homogenous distribution of condensed spherical shaped particles and small grains on the glass substrate surface. Moreover, the optical analyses exhibit that the films have a high transmittance in the visible range of up to 87%. Moreover, the addition of (Al) led to variation in the films optical band gap from 3.64 to 3.73 eV. In addition, the FTIR spectra confirmed the successful formation of the TiO₂ phase in all samples. The photoluminescence (PL) spectra exhibited emission peaks located in the ultraviolet and visible regions for all samples. The films electrical resistivity showed an apparent dependence on Al content, which substantially decreases with the increasing Al concentration from 9.5 × 10⁻² to 9 × 10⁻³ Ω.cm.</p> Graphical Abstract <p></p>