Donald Leroy "Don" LaFontaine (August 26, 1940 – September 1, 2008) was an American voice actor who recorded more than 5,000 film trailers and thousands of television advertisements, network promotions, and video game trailers.

He became identified with the phrase "In a world...", used in so many movie trailers that it became a cliché. Widely known in the film industry, the man whose nicknames included "Thunder Throat" and "The Voice of God", became known to a wider audience through commercials for GEICO insurance and the Mega Millions lottery game.