William Ernest Metzger was an automotive pioneer and salesman from Detroit. He opened one of the first automobile dealerships in the United States, and participated in the early development of a number of early automobile companies, including the Cadillac Automobile Company and the E-M-F Company, in which the "M" stands for his name.

The E-M-F Company was an early American automobile manufacturer that produced automobiles from 1909 to 1912. The name E-M-F was gleaned from the initials of the three company founders: Barney Everitt, William Metzger, and Walter Flanders.