Human social life is structured by social norms creating both obligations and entitlements. Recent research has found that young children enforce simple obligations against norm violators by protesting. It is not known, however, whether they understand entitlements in the sense that they will actively object to a second party attempting to interfere in something that a third party is entitled to do-what we call counter-protest. In two studies, we found that 3-year-old children understand when a person is entitled to do something, and so they actively defend this person's entitlement against unjustified interference from second parties. In some cases, they even enforce second-order entitlements, for example, in the case of ownership where an owner is entitled to entitle others to use the owner's property.