James Buchanan Duke (born in Durham, North Carolina, 1856; died 1925) was a U.S. tobacco industrialist. His father, Washington Duke, had owned a tobacco company which James B. Duke took over in the 1880s. In 1885, Duke acquired an advantageous license to use the first automated cigarette making machine, and by 1890, Duke controlled 40% of the American cigarette market (then known as pre-rolled tobacco). In that year, Duke consolidated control of his four major competitors under one corporate entity, the American Tobacco Company. Duke then used his monopoly control over the American cigarette market to engage in predatory pricing in the remaining American tobacco markets: plug or chewing tobacco, and loose smoking tobacco.

In the 1890s, he forged an agreement with his British competitors to divide the market, with Duke controlling the American trade, the British companies controlling the trade in British territories, and a third, cooperative venture between the two - the British-American Tobacco Company - controlling the sale of tobacco to the rest of the world. During this time, Duke was repeatedly sued by business partners and shareholders who alleged that he had engaged in shady, self-serving business deals.

Duke was married several times, and had longrunning affairs with at least one mistress. The Court of Chancery of New Jersey reported a case in 1905 wherein Duke divorced his wife of less than two years, who had previously been his mistress for a decade.

In 1911, the United States Supreme Court upheld an order breaking up the American Tobacco Company's monopoly. The company was then divided into several smaller enterprises, of which only the British-American Tobacco Company remained in Duke's control. Nevertheless, Duke continued to collude with the other companies to maintain high tobacco prices until his death in 1925.

In December of 1924, Duke endowed Duke University, naming it for his father. He left approximately one third of his estate to the University, dividing the remainder between North Carolina and South Carolina hospitals, universities, orphanages, and churches.