Alexander S. Williams (July 9, 1839 – March 25, 1917) was an American law enforcement officer and police inspector for the New York City Police Department. One of the more colorful yet controversial figures of the NYPD, popularly known as "Clubber Williams" or "Czar of the Tenderloin", he oversaw the Tenderloin and Gas House districts as well as breaking up a number of the city's street gangs, most notably, the Gas House Gang in 1871. He, along with William "Big Bill" Devery and Thomas F. Byrnes, were among several senior NYPD officials implicated by the Lexow Committee during the 1890s.