The anisotropic [Formula: see text] factors of the deoxygenated YBaCuO (Y123) are theoretically studied using the perturbation formulas of the [Formula: see text] factors for a tetragonally elongated octahedral [Formula: see text] cluster. The ligand orbital and spin-orbit coupling contributions are included from the cluster approach in view of covalency. The calculated [Formula: see text] factors show good agreement with the experimental data. The anisotropy of the [Formula: see text] factors is analyzed by considering the local tetragonal elongation distortion around this five-fold coordinated [Formula: see text] site in the deoxygenated Y123 system.