The acceleration effect from the addition of N-fluorobenzenesulfonimide (NFSI) to a samarium(III) triflate catalyzed Meyer–Schuster rearrangement under microwave irradiation was studied. Reaction rate plots indicate that the Sm(OTf)3/NFSI system is especially suitable for unreactive substrates towards the Meyer–Schuster rearrangement. The mechanism was probed by a crossover experiment using 18O-labeled substrates.