Cross-linked micelles are used to generate large uniform mesopores in silsesquioxane-based thin films. To our knowledge, this is first time cross-linked micelles have been used for this type of application. The cross-linked micelles are fabricated from amphiphilic block copolymers to compatibilize large immiscible domains in the organosilicate. Measured pore sizes range from 20 to 30 nm depending on the porogen loading level. The spherical morphology is maintained over a wide range of porogen loading (5 to 50% wt.) as analyzed by scanning electron microscopy and ellipsometric porosimetry. The low-k porous films are stable in water as a result of the hydrophobic nature of the material, and the films can be stacked to form independent dielectric layers for numerous applications. © 2013 American Chemical Society.