Abstract 6Li, 7Li, and 29Si high-field static NMR studies of lithium-potassium mixed alkali glasses are reported. The fractional contribution to the spectral intensity of the various Q n units and the values of the chemical shift tensors for each of the sites are determined as a function of alkali composition. The dependence of the linewidths of the lithium spectra as a function of lithium-to-potassium ratio is evidence of like-alkali cation pairing in these glasses. The structure of borate glasses, pure vitreous B 2O 3,Li 2O·B 2O 3, and 2Na 2O·B 2O 3 was investigated with 10B and 11B NQR. Some structural sites that have not been resolved by NMR alone are not found.