Pure and Al-doped ZnO ceramics have been successfully synthesized by conventional sintering high pressure treated nano powders. Results reveal that Al3+ has been completely incorporated in the ZnO matrix. The dielectric study of the prepared samples showed an enhancement in the dielectric constant (∼1.39 × 104 at 1 kHz) at room temperature due to Al-doping. The conductivity of ZnO ceramics was also increased through incorporation of Al ions in the ZnO lattice due to the increased number of charge carriers. Therefore, the simple and low cost fabrication of Al-doped ZnO ceramics and its giant dielectric properties make this material very interesting for high dielectric applications.