Suppose it is a law that all Fs are G. Does the law hold in all possible worlds? According to Necessitarianism, it holds in at least all those worlds containing F-ness. I argue that the Necessitarian must also take the law to hold in all those possible worlds which do not contain F-ness. Accepting the principle that a law can only hold in a world if it has some ontological grounding in that world, I argue that Necessitarianism is committed to (...) the claim that any law holding in the actual world is grounded in every possible world, and that any law holding in any possible world is grounded in the actual world. In other words, Necessitarianism takes all possible laws to be actual. (shrink)