William Darrell Mays Jr. (July 20, 1958 – June 28, 2009) was an American television direct-response advertisement salesperson. Throughout his career, he promoted a wide variety of products, including OxiClean, Orange Glo, Kaboom, Zorbeez, and Mighty Mendit. His promotions aired mainly on the Home Shopping Network through his company, Mays Promotions, Inc., although they have aired on other syndicated networks. Mays's infomercials were known for his catch phrase "Hi, Billy Mays here", and his shouted delivery of lines.

Mays and his business partner, Anthony Sullivan, were also featured on PitchMen, a Discovery Channel television series that documented their work. His distinctive beard, attire, loud voice, and impassioned sales pitches made him a recognized television presence in the United States and Canada.