John Francis Queeny (August 17, 1859 – March 19, 1933) was an American businessman, known for founding Monsanto Chemical Works (later Monsanto) in St. Louis, Missouri, on September 26, 1901, with $5,000.

Two years later, he spent his life savings in purchasing a sulfur refinery; it burned down the next day.

Two years after that, he founded Monsanto Chemical Works, and began producing saccharine, which he sold to Meyer Brothers.

He started to turn a profit in 1905, but it was not until 1906 that he left Meyer Brothers to work for Monsanto full-time.

The company grew to become one of the largest producers of engineered crops in the United States by the 1970s.