An extended version of the Maz'ya-Shaposhnikova theorem on the limit as s -> 0(+) of the Gagliardo-Slobodeckij fractional seminorm is established in the Orlicz space setting. Our result holds in fractional Orlicz-Sobolev spaces associated with Young functions satisfying the Delta(2)-condition, and, as shown by counterexamples, it may fail if this condition is dropped.