The Mercedes-Benz W221 is a chassis code of the fifth generation S-Class produced from August 2005 until June 2013.

The Mercedes-Benz S-Class, formerly known as Sonderklasse, is a series of full-sized luxury sedans, limousines and armored sedans produced by the German automaker Mercedes-Benz. The S-Class is the designation for top-of-the-line Mercedes-Benz models and was officially introduced in 1972 with the W116, and has remained in use ever since. The S-Class is the flagship vehicle for Mercedes-Benz and is positioned above the other models.