Juan Bautista Rogers Cooper (born John Rogers Cooper on September 11, 1791, Alderney, British Channel Islands – June 2, 1872, San Francisco, California) was a 19th-century pioneer of California, who held British, Mexican, and finally American citizenship. Raised in Massachusetts in a maritime family, he came to the Mexican territory of Alta California as master of the ship Rover, and was a pioneer of Monterey, California, when it was the capital of the territory. He converted to Catholicism, became a Mexican citizen, married the daughter of the Mexican territorial governor, and acquired extensive land holdings in the area prior to the Mexican–American War.