AbstractHyperconnected hybrid organosilicate glass networks formed by hyperstiff precursor molecules with certain geometrical characteristics can lead to exceptional elastic properties superior to that of fully dense silica. Carbon‐ and silicon‐containing precursors with defined molecular planarity are introduced and a new design strategy where both the network connectivity and the precursor geometry are effectively utilized to enhance elastic properties is proposed. The geometrical features rendering a precursor molecule as hyperstiff are identified through molecular dynamics simulations and constraint analyses by calculating the degree of nonaffine deformations. Nonaffine deformations have not been previously examined for organosilicate hybrid glass networks and are a fundamental new approach to reveal the combined impact of precursor geometry and connectivity on the mechanical behavior of hybrid glass networks.