The 17O NMR chemical shielding tensors and chemical shift for a set of substituted benzyl ethers derivatives containing (methyl, ethyl, isopropyl, t-butyl, brome and lithium) have been calculated. The molecular structures were fully optimized using B3LYP/6-31G(d,p). The calculation of the 17O shielding tensors employed the GAUSSIAN 98 implementation of the gauge-including atomic orbital (GIAO) and continuous set of gauge transformations (CSGT) by using 6-31G (d,p), 6-31++G(d,p) and 6-311++G(d,p) basis set methods at density functional levels of theories (DFT). The values determined using the GIAO and CSGT were found to give a good agreement with the experimental chemical shielding.