William "Billy" Barnes Jr. (November 17, 1866 – June 25, 1930) was a newspaper publisher and politician who rose to the position of political "boss" for the Republican Party in Albany County. Barnes served as the Republican committee’s chairman from 1911 to 1914. He was also the owner and publisher of the Albany Evening Journal.

Barnes could be willfully cagey about his role as the political boss in Albany. As described in an October 24, 1911, New York Times article, "Barnes Dodges All Political Questions", Barnes was evasive when responding to questions posed by a New York State Senate committee meeting investigating how Albany was being run. When asked by the Committee's counsel "You are the leader of the political party in this county, are you not?" Barnes, replied "I don’t recognize any such office." His evasiveness continued from there.

In addition to his local influence in Albany, Barnes played a major role in national politics, working with Thomas C. Platt to secure presidential victories for William McKinley, Theodore Roosevelt, and William Howard Taft. When Roosevelt later ran as an independent (against Taft), he accused Barnes of being a corrupt party boss in league with Charles Murphy, the "Boss" of the Democrat-run Tammany Hall political machine. Barnes sued Roosevelt for libel in 1915, but ultimately lost in court.

The Barnes political machine in Albany ended in 1921 with the mayoral victory of Democrat William Hackett.

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