An efficient protocol for the synthesis of substituted oxazoles via an annulation of ketones, DMSO, and ammonium is reported. DMSO is first found to serve as oxygen donor in annulation resulting in regioselective synthesis of 2,4‐disubstituted oxazoles. With the optimized conditions in hand, 22 examples of 2,4‐disubstituted oxazoles are obtained from readily available substrates. The protocol can be