William T. "Cocktail Bill" Boothby (November 10, 1862, San Francisco – August 4, 1930, San Francisco) was an American bartender and writer of San Francisco, California in the years before and after the 1906 San Francisco earthquake. He tended bar for many years at San Francisco's Palace Hotel. He also served in the California State Assembly for the 43rd district from 1895 to 1897.