A device and method to prevent delamination at load-bearing apertures in structural composite substrates is disclosed. The device is a composite reinforcing grommet having a hollow, generally tubular member of braided filaments impregnated with polymer. The member may be radially deformed for insertion into an aperture in a structural composite substrate and is then capable of being radially expanded to form flanges to secure the structural composite between the flanges. A method of reinforcing a substrate having an aperture therethrough including the step of cobonding a composite reinforcing grommet to a structural composite substrate is also disclosed.