The dependence of a $^{29}$Si geminal J coupling across the inter-tetrahedral linkage on local structure was examined using first-principles DFT calculations. The two main influences on $^2J_\mathrm{Si–O–Si}$ were found to be a primary dependence on the linkage Si–O–Si angle and a secondary dependence on mean Si–O–Si linkage of the two coupled $^{29}$Si nuclei. An analytical expression describing these dependencies was proposed and used to develop an approach for relating the correlated pair of $^2J$ Si-O-Si coupling and mean $^{29}$Si isotropic chemical shift to the linkage Si–O–Si angle and the mean Si–O–Si angle of the two coupled $^{29}$Si nuclei. An example of this analysis is given using $^{29}$Si NMR results from the siliceous zeolite Sigma-2.