Nanocomposite microcapsules for self-healing of composites. The nanocomposite microcapsules comprise a urea-formaldehyde shell encompassing a liquid core of polymerizable healing agent. The microcapsules further comprise nanoparticulates encompassed in the core and also present on the outer surface of the microcapsule shell. Self-healing composites with the nanocomposite microcapsules embedded in the composite polymer matrix are also described. Methods of making and using the same are also disclosed.