The deposition of undoped, aluminum and/or holmium doped and co-doped zinc oxide thin films on different substrates was achieved using a very simple and versatile aqueous solution method. The effect of the precursor solution concentration on the morphological and structural characteristics, as well as on the optical properties of the undoped ZnO thin films was also investigated. The AFM investigations have revealed that the morphology of the films is smooth and homogeneous. The room-temperature photoluminescence (PL) and the optical absorption (UV–vis) properties of the as-obtained undoped and doped ZnO thin films were investigated, as well. A strong UV emission (380nm) was recorded for the undoped, aluminum and holmium doped and co-doped ZnO thin films. The band gap value obtained for the doped ZnO thin films is ranging between 3.01eV and 3.56eV, depending on the nature and the concentration of the dopant.